Answer
Hint:- In 8 years money from Interest will be come equal to the principal
amount invested. So, money had been doubled in 8 years.
Let the initial amount of money invested will be Rs. x.
Then after 8 years money had become 2x.
Out of Rs. 2x, money from interest will be 2x – initial amount invested = 2x – x = x.
Let the rate of interest be r.
So, now we will use a simple interest formula.
According to Simple Interest (S.I) formula.
\[ \Rightarrow S.I. =
\dfrac{{PRT}}{{100}}\].
Where P is principal amount, R is rate of interest and T will be time period.
So, putting the values in the above formula. We will get,
\[ \Rightarrow x = \dfrac{{xr(8)}}{{100}}\]
On solving the above equation. We will get,
\[ \Rightarrow {\text{ }}r{\text{ }} = {\text{ }}\dfrac{{100}}{8}{\text{ }} = {\text{ }}12.5\]
Hence, the rate of interest to double a money in 8 years will be 12.5% per annum.
Note:- Whenever we came up with this type of problem where we are asked
to
find rate of interest then first, we will find the interest on principal amount by
subtracting principal amount from the money after 8 years and then we will
assume rate of interest to be r and then apply, Simple Interest formula and
find the required value of rate of interest.
Chapter 13: SIMPLE INTEREST
Introduction
Simple interest is calculated as
P * R * T / 100
Where P = Principal or the amount borrowed
R = Rate of interest
T = years
Note: The day on which money is deposited isn't counted but date on which money is withdrawn is counted.
Relation Among Principal, Time, Rate Percent of Interest Per Annum and Total Interest :
Amount = Principal + Total interest
A = P + \( \frac{P * t * r}{100} \)
Time = \( \frac{\text{Total interest}}{\text{Interest on the principal in one year}} \). Thus, if we have the total interest as ` 300 and the interest per year is ` 50, then we can say that the number of years is 300/50 = 6 years.
COMPOUND INTEREST
Let principal = P, time = n years and rate = r% per annum and let A be the total amount at the end of n years, then A = P[\( 1 + \frac{r}{100} \)]n
When compound interest is reckoned half-yearly. If the annual rate is r% per annum and is to be calculated for n years. Then in this case, rate = (r/2)% half-yearly and time = (2n) half-years then A = P[\( 1 + \frac{r/2}{100} \)]2n
When compound interest is reckoned quarterly. In this case, rate = (r/4)% quarterly and time = (4n) quarter years. \ As before, then A = P[\( 1 + \frac{r/4}{100} \)]4n
The difference between the compound interest and the simple interest over two years is given by \( \frac{P * r^2}{100^2} \)
Q.
The SI on a sum of money is 25% of the principal, and the rate per annum is equal to the number of years. Find the rate percent.
4.5
6
5
8
Ans .
5- Explanation :Let principal = x, time = t years Then interest = x/4, rate = t% Now, using the SI formula, we get Interest = (Principal × Rate × Time)/100 so x/4 = (x × t × t)/100 so t2 = 25 and we get t = 5%
Q.
The rate of interest for first 3 years is 6% per annum, for the next 4 years, 7 per cent per annum and for the period beyond 7 years, 7.5 percentages per annum. If a man lent out ` 1200 for 11 years, find the total interest earned by him?
1002
912
864
948
Ans .
912- Explanation :Whenever it is not mentioned whether we have to assume SI or CI we should assume SI. For any amount, interest for the 1st three years @ 6% SI will be equal to 6 × 3 = 18% Again, interest for next 4 years will be equal to 7 × 4 = 28%. And interest for next 4 years (till 11 years) –7.5 × 4 = 30% So, total interest = 18 + 28 + 30 = 76% So, total interest earned by him = 76% of the amount = (76*1200 / 100) = 912
Q.
A sum of money doubles itself in 12 years. Find the rate percentage per annum
12.5%
8.33%
10%
7.51%
Ans .
8.33%- Explanation :Let principal = x, then interest = x, time = 12 years. Using the formula, Rate = (Interest × 100)/Principal × Time = (x × 100)/(x × 12) = 8.33%
Q.
A certain sum of money amounts to ` 704 in 2 years and ` 800 in 5 years. Find the principal.
580
600
660
640
Ans .
640- Explanation :Let the principal be ` x and rate = r%. Then, difference in between the interest of 5 years and of 2 years equals to ` 800 – ` 704 = ` 96 So, interest for 3 years = ` 96 Hence, interest/year = ` 96/3 = ` 32 So, interest for 2 years Æ 2 × ` 32 = ` 64 So, the principal = ` 704 – ` 64 = ` 640
Q.
A sum of money was invested at SI at a certain rate for 3 years. Had it been invested at a 4% higher rate, it would have fetched ` 480 more. Find the principal.
4000
4400
5000
3500
Ans .
4000- Explanation :Let the rate be y% and principal be ` x and the time be 3 years. Then according to the question = (x(y + 4) × 3)/100 – (xy × 3)/100 = 480 so xy + 4x – xy = 160 × 100 so x = (160 × 100)/4 = ` 4000
Q.
A certain sum of money trebles itself in 8 years. In how many years it will be five times?
22
16
20
24
Ans .
16- Explanation :It trebles itself in 8 years, which makes interest equal to 200% of principal. So, 200% is added in 8 years. Hence, 400%, which makes the whole amount equal to five times of the principal, which will be added in 16 years.
Q.
If CI is charged on a certain sum for 2 years at 10% the amount becomes 605. Find the principal?
550
450
480
500
Ans .
500- Explanation :Using the formula, amount = Principal (1 + rate/100)time 605 = p(1 + 10/100)2 = p(11/10)2 p = 605(100/121) = ` 500
Q.
If the difference between the CI and SI on a certain sum of money is ` 72 at 12 per cent per annum for 2 years, then find the amount.
6000
5000
5500
6500
Ans .
5000- Explanation :Simple interest and compound interest for the first year on any amount is the same. Difference in the second year’s interest is due to the fact that compound interest is calculated over the first year’s interest also. Hence, we can say that ` 72 = Interest on first year’s interest Æ 12% on first year’s interest = ` 72. Hence, first year’s interest = ` 600 which should be 12% of the original capital. Hence, original capital = ` 5000 (this whole process can be done mentally).
Q.
The population of Jhumri Tilaiya increases by 10% in the first year, it increases by 20% in the second year and due to mass exodus, it decreases by 5% in the third year. What will be its population after 3 years, if today it is 10,000?
11,540
13,860
12,860
12,540
Ans .
12,540- Explanation :Population at the end of 1 year will be Æ 10,000 + 10% of 10,000 = 11,000 At the end of second year it will be 11,000 + 20% of 11,000 = 13,200 At the end of third year it will be 13,200-5% of 13,200 = 12,540.
Q.
Seth Ankoosh Gawdekar borrows a sum of ` 1200 at the beginning of a year. After 4 months, ` 1800 more is borrowed at a rate of interest double the previous one. At the end of the year, the sum of interest on both the loans is ` 216. What is the first rate of interest per annum?
9
6
8
12
Ans .
6- Explanation :Let the rate of interest be = r% Then, interest earned from ` 1200 at the end of year = (1200r)/100 = ` 12r Again, interest earned from ` 1800 at the end of year = (1800/100) × (8/12) × 2r = ` 24r So, total interest earned = 36r, which equals 216 fi r = 216/36 = 6%
Q.
1200 is lent out at 5% per annum simple interest for 3 years. Find the amount after 3 years
1380
1290
1470
1200
Ans .
1380- Explanation :The annual interest would be ` 60. After 3 years the total value would be 1200 + 60 × 3 = 1380
Q.
Interest obtained on a sum of ` 5000 for 3 years is ` 1500. Find the rate percen
8
9
10
11
Ans .
10- Explanation :The interest earned per year would be 1500/3=500. This represents a 10% rate of interest
Q.
2100 is lent at compound interest of 5% per annum for 2 years. Find the amount after two years
2300
2315.25
2310
2320
Ans .
2315.25- Explanation :2100 + 5% of 2100 = 2100 + 105 = 2205 (after 1 year). Next year it would become: 2205 + 5% of 2205 = 2205 +110.25 = 2315.25
Q.
1694 is repaid after two years at compound interest. Which of the following is the value of the principal and the rate?
1200, 20%
1300, 15%
1400, 10%
1500, 12%
Ans .
1400, 10%- Explanation :1400 increased by 10% gives 1540 increased by 10% gives 1694.
Q.
Find the difference between the simple and the compound interest at 5% per annum for 2 years on a principal of ` 2000
5
10.5
4.5
5.5
Ans .
5- Explanation :Simple Interest for 2 years = 100 + 100 = 200. Compound interest for 2 years: Year 1 = 5% of 2000 = 100. Year 2: 5% of 2100 = 105 Æ Total compound interest = ` 205. Difference between the Simple and Compound interest = 205 – 200 = ` 5
Q.
Find the rate of interest if the amount after 2 years of simple interest on a capital of ` 1200 is ` 1440
8
9
10
11
Ans .
10- Explanation :Interest in 2 years = ` 240. Interest per year = ` 120 Rate of interest = 10%
Q.
After how many years will a sum of ` 12,500 become ` 17,500 at the rate of 10% per annum?
2
3
4
5
Ans .
4- Explanation :12500 @ 10% simple interest would give an interest of ` 1250 per annum. For a total interest of 5000, it would take 4 years.
Q.
What is the difference between the simple interest on a principal of ` 500 being calculated at 5% per annum for 3 years and 4% per annum for 4 years?
5
10
20
40
Ans .
5- Explanation :5% for 3 years (SI) = 15% of the amount; At the same time 4% SI for 4 years means 16% of the amount. The difference between the two is 1% of the amount. 1% of 500 = ` 5
Q.
What is the simple interest on a sum of `700 if the rate of interest for the first 3 years is 8% per annum and for the last 2 years is 7.5% per annum?
269.5
283
273
280
Ans .
273- Explanation :8% @ 700 = ` 56 per year for 3 years 7.5% @ 700 = ` 52.5 per year for 2 years Total interest = 56 × 3 + 52.5 × 2 = 273
Q.
What is the simple interest for 9 years on a sum of ` 800 if the rate of interest for the first 4 years is 8% per annum and for the last 4 years is 6% per annum?
400
392
352
cant say
Ans .
cant say- Explanation :8% of 800 for 4 years + 6% of 800 for 4 years = 64 × 4 + 48 × 4 = 256 + 192 = 448. However, we do not know the rate of interest applicable in the 5 th year and hence cannot determine the exact simple interest for 9 years
Q.
What is the difference between compound interest and simple interest for the sum of ` 20,000 over a 2 year period if the compound interest is calculated at 20% and simple interest is calculated at 23%?
400
460
440
450
Ans .
400- Explanation :Simple interest @ 23% = 4600 × 2 = 9200 Compound interest @ 20% 20000 increase of 20% 24000 increase of 20% 28800 so` 8800 compound interest. Difference = 9200 – 8800 = ` 400
Q.
Find the compound interest on ` 1000 at the rate of 20% per annum for 18 months when interest is compounded half-yearly
331
1331
320
325
Ans .
331- Explanation :1000 increase of 10% gives 1100 increase of 10% gives 1210 increase of 10% gives 1331. Compound interest = 1331 – 1000 = ` 331
Q.
Find the principal if the interest compounded at the rate of 10% per annum for two years is ` 420
2000
2200
1000
1100
Ans .
2000- Explanation :Solve using options. Thinking about option (a): 2000 gives 2200 (after 1 year) gives 2420 (after 2 years) which gives us an interest of `420 as required in the problem. Hence, this is the correct answer
Q.
Find the principal if compound interest is charged on the principal at the rate of 16 % per annum for two years and the sum becomes ` 196
140
154
150
144
Ans .
144- Explanation :P × 7/6 × 7/6 = 196 gives P = (196 × 6 × 6)/7 × 7 = 144
Q.
The SBI lent ` 1331 to the Tata group at a compound interest and got ` 1728 after three years. What is the rate of interest charged if the interest is compounded annually?
11
9.09
12
8.33
Ans .
9.09- Explanation :1331 × 1.090909 × 1.090909 × 1.090909 = 1331 × 12/11 × 12/11 × 12/11 = 1728. Hence, the rate of compound interest is 9.09%.
Q.
In what time will ` 3300 become ` 3399 at 6% per annum interest compounded half-yearly?
6 months
1 year
1.5 years
3 months
Ans .
6- Explanation :Since compounding is half yearly, it is clear that the rate of interest charged for 6 months would be 3%. Thus we get 3300 gives 3% increase and we get 3399
Q.
Ranjan purchased a Maruti van for ` 1,96,000 and the rate of depreciation is 14 2/7% per annum. Find the value of the van after two years
140000
144000
150000
160000
Ans .
144000- Explanation :The value of the van would be 196000 × 6/7 × 6/7 = 144000
Q.
At what percentage per annum, will ` 10,000 amount to 17,280 in three years? (Compound Interest being reckoned)
20
14
24
11
Ans .
20- Explanation :Solve through options: 10000 with 20% increase gives 12000 with 20% increase gives 14400 with 20% increase gives 17280.
Q.
Vinay deposited ` 8000 in ICICI Bank, which pays him 12% interest per annum compounded quarterly. What is the amount that he receives after 15 months?
9274.2
9228.8
9314.3
9338.8
Ans .
9274.2- Explanation :12% per annum compounded quarterly means that the amount would grow by 3% every 3 months. Thus, 8000 gives 8000 + 3% of 8000 = 8240 after 3 months gives 8240 + 3% of 8240 = 8487.2 after 6 months and so on till five3 month time periods get over. It can be seen that the value would turn out to be 9274.2.
Q.
What is the rate of simple interest for the first 4 years if the sum of ` 360 becomes ` 540 in 9 years and the rate of interest for the last 5 years is 6%?
4
5
3
6
Ans .
5- Explanation :For the last 5 years, the interest earned would be: 30% of 360 = 108. Thus, interest earned in the first 4 years would be ` 72 and ` 18 every year on an amount of ` 360- which means that the rate of interest is 5%
Q.
Harsh makes a fixed deposit of ` 20,000 with the Bank of India for a period of 3 years. If the rate of interest be 13% SI per annum charged half-yearly, what amount will he get after 42 months?
27800
28100
29100
28500
Ans .
29100- Explanation :He will get 20000 + 45.5% of 20000 = 29100. [Note: In this case we can take 13% simple interest compounded half yearly to mean 6.5% interest getting added every 6 months. Thus, in 42 months it would amount to 6.5 × 7 = 45.5%
Q.
Ranjeet makes a deposit of ` 50,000 in the Punjab National Bank for a period of years. If the rate of interest is 12% per annum compounded half-yearly, find the maturity value of the money deposited by him.
66,911.27
66,123.34
67,925.95
65,550.8
Ans .
66911.27- Explanation :50000 gives with a 6% interest per annum 53000 gives with a 6% interest per annum 56180 gives with a 6% interest per annum 59550.8 gives with a 6% interest per annum 63123.84 gives with a 6% interest per annum 66911.27
Q.
Vinod makes a deposit of ` 100,000 in Syndicate Bank for a period of 2 years. If the rate of interest be 12% per annum compounded half-yearly, what amount will he get after 2 years?
122,247.89
125,436.79
126,247.69
122436.89
Ans .
126247.69- Explanation :100000 + 6% of 100000 (after the first 6 months) = 106000. After 1 year: 106000 + 6% of 106000 = 112360 After 1 ½ years: 112360 + 6% of 112360 = 119101.6 After 2 years: 119101.6 + 6% of 119101.6 = 126247.69
Q.
What will be the simple interest on ` 700 at 9% per annum for the period from February 5, 1994 to April 18, 1994?
12.60
11.30
15
13
Ans .
12.6- Explanation :(73/365) × 0.09 × 700 = ` 12.6. (Since the time period is 73 days)
Q.
Ajay borrows ` 1500 from two moneylenders. He pays interest at the rate of 12% per annum for one loan and at the rate of 14% per annum for the other. The total interest he pays for the entire year is ` 186. How much does he borrow at the rate of 12%?
1200
1300
1400
300
Ans .
1200- Explanation :The average rate of interest he pays is 186 × 100/1500 = 12.4%. The average rate of interest being 12.4%, it means that the ratio in which the two amounts would be distributed would be 4:1 (using alligation). Thus, the borrowing at 12% would be ` 1200
Q.
A sum of money placed at compound interest doubles itself in 3 years. In how many years will it amount to 8 times itself?
9
8
27
7
Ans .
9- Explanation :If it doubles in 3 years, it would become 4 times in 6 year and 8 times in 9 years
Q.
A difference between the interest received from two different banks on ` 400 for 2 years is ` 4. What is the difference between their rates?
0.5
0.2
0.23
0.52
Ans .
0.5- Explanation :The difference in Simple interest represents 1% of the amount invested. Since this difference has occurred in 2 years, annually the difference would be 0.5%.
Q.
A sum of money doubles itself in 5 years. In how many years will it become four fold (if interest is compounded)?
15
10
20
12
Ans .
10- Explanation :It would take another 5 years to double again. Thus, a total of 10 years to become four fold
Q.
A sum of money becomes 4 times at simple interest in 10 years. What is the rate of interest?
10
20
30
40
Ans .
30- Explanation :The sum becomes 4 times Æ the interest earned is 300% of the original amount. In 10 years the interest is 300% means that the yearly interest must be 30%
Q.
What annual payment will discharge a debt of ` 808 due in 2 years at 2% per annum?
200
300
400
350
Ans .
400- Explanation :A × (1.02) + A = 808 × (1.02) 2 Æ A = ` 400
Q.
In what time will ` 8000 amount to 40,000 at 4% per annum? (simple interest being reckoned)
100
50
110
160
Ans .
100- Explanation :The value would increase by 4% per year. To go to 5 times it’s original value, it would require an increment of 400%. At 4% SI it would take 100 years
Q.
Raju lent ` 400 to Ajay for 2 years, and ` 100 to Manoj for 4 years and received together from both ` 60 as interest. Find the rate of interest, simple interest being calculated
5
6
8
9
Ans .
- Explanation :Total effective amount lent for 1 year = ` 400 × 2 + ` 100 × 4 = ` 1200 Interest being ` 60, Rate of interest 5%
Q.
If the difference between the simple interest and compound interest on some principal amount at 20% per annum for 3 years is ` 48, then the principle amount must be
550
500
375
400
Ans .
375- Explanation :Solve using options. If we try 500 (option b) for convenience, we can see that the difference between the two is ` 64 (as the SI would amount to 300 and CI would amount to 100 + 120 + 144 = 364). Since, we need a difference of only ` 48 we can realize that the value should be 3/4 th of 500. Hence, 375 is correct
Q.
Shashikant derives an annual income of ` 688.25 from ` 10,000 invested partly at 8% p.a. and partly at 5% p.a. simple interest. How much of his money is invested at 5% ?
5000
4225
4800
3725
Ans .
3725- Explanation :The average Rate of interest is 6.8825%. The ratio of investments would be 1.1175: 1.8825 (@5% is to 8%). The required answer = 10000 × 1.1175/3 = 3725
Q.
In what time will ` 500 give ` 50 as interest at the rate of 5% per annum simple interest?
2
5
3
4
Ans .
2- Explanation :Interest per year = ` 25. Thus, an interest of ` 50 would be earned in 2 years.
Q.
In what time will the simple interest on ` 1750 at 9% per annum be the same as that on ` 2500 at 10.5% per annum in 4 years?
6 years and 8 months
7 years and 3 months
6 years
7 years and 6 months
Ans .
6 years and 8 months- Explanation :42% on 2500 = ` 1050. The required answer would be: 1050/157.5 = 6 years and 8 months.
Q.
Two equal sums were borrowed at 8% simple interest per annum for 2 years and 3 years respectively. The difference in the interest was ` 56. The sum borrowed were
690
700
740
780
Ans .
700- Explanation :The difference would amount to 8% of the value borrowed. Thus 56 = 0.08 × sum borrowed in each case becomes Sum borrowed = ` 700.
Q.
A sum of money is borrowed and paid back in two equal annual instalments of ` 882, allowing 5% compound interest. The sum borrowed was
1640
1680
1620
1700
Ans .
1640- Explanation :882 × (1.05) + 882 = P × (1.05)2 Solve for P to get P = 1640
Q.
The difference between simple and compound interest on a sum of money at 5% per annum is ` 25. What is the sum?
5000
10000
4000
data insufficient
Ans .
data insufficient- Explanation :The data is insufficient as we do not know the time period involved.
Q.
A sum was invested at simple interest at a certain interest for 2 years. It would have fetched ` 60 more had it been invested at 2% higher rate. What was the sum?
1500
1300
2500
1000
Ans .
1500- Explanation :Based on the information we have, we can say that there would have been ` 30 extra interest per year. For 2% of the principal to be equal to ` 30, the principal amount should be ` 1500
Problems
Q. Find the simple interest on Rs. 3000 at rate of interest 6 1/4% for 73 days
A. 73 days = 73/365 = 1/5 yrs.
SI = (3000 * 25/4 * 1/5) / 100
Q. An amount loaned at interest rate 13.5% per annum becomes Rs. 2502.50 after 4 years. Find the sum.
A. P + SI = P + P * 13.5 * 4 / 100 (Adding P on both sides)
2502.5 = P ( 1 + 54/100)
2502.5 = P (1.54)
P = 2502.5 / 1.54 = 1625
Q. A borrowed money at interest rate 6% for first two years, 9% for next three years and 14% for period beyond 5 years. If he pays a total interest of Rs. 11400 after 9 yrs how much did he borrow?
A. 11400 = (P *6*2/100) + (P*9*3/100) + (P*14*4/100)
11400 = (12+27+56)P / 100
11400 * 100 / 95 = P
P = 12000
Q. A certain sum of money amounts to Rs 1008 in 2 years and Rs. 1164 in 3.5 yrs.Find sum and RI
A. SI for 1.5 yrs = 1164 - 1008 = 156
SI for 1 yrs = 156 * 2 / 3 = 104 and two years = 208.
Principal = 1008 - 208 = 800
Use simple interest formula to get RI.
Q. A sum of 1500 is lent in 2 parts where one is at 8% and second is at 6%. If the total annual income is Rs. 106, find money lent at each rate.
A. (x*1*8/100) + ((1500-x) * 1 * 6 / 100 ) = 106
8x/100 + (9000 - 6x)/100 = 106
8x +9000 - 6x = 10600
2x = 1600
x=800
Compound Interest
When P = principal, n = years and R = rate of interest compounded annually
The Amount = P (1+R/100)^n
When P = principal, R = rate of interest compounded half yearly theAmount = P ( 1 + (R/2) / 100)^2nWhen P = principal, R = rate of interest compounded quarterly the
Amount = P ( 1 + (R/4) / 100)^4nWhen P = principal, R = rate of interest compounded annually but the time is in fraction then like 3 2/5 yrs
Amount = P ( 1 + R / 100)^3 * (1 + (2R/5)/100)
When P = principal, R = rate of interest compounded annually but is different for first year R1, second year R2 and third year R3 then
Amount = P ( 1 + R1 / 100) * ( 1 + R2 / 100) * ( 1 + R3 / 100)
Present worth of Rs. x due n years hence is
Present worth = x / (1 + R/100)^n
Solved Problems
Q. Find CI on Rs.7500, compounded annually at RI of 4% for 2 years.
A. Amount = 7500 * (1 + 4/100)^2
Then amount - 7500 gives CI.
Q. CI is compounded half yearly, principal = Rs. 10000 in rate 4% for 2 years.
A. Amount = 10000( 1+ 2/100)^4
Amount = 10824.32
CI = Amount - principal = 10824.32 - 10000 = 824.32
Q. Difference between SI and CI accrued on an amount of Rs. 18000 in 2 years is Rs.405. What is the RI.
A. P( 1+ (R/100) )^n - P*R*T/100 = 405
{18000 ( 1 + (R/100))^2 - 18000} - (18000 * R * 2 / 100) = 405
Solving this you can get R.
Q. Divide 1301 between A and B such that the amount of A after 7 years is equal to amount in B after 9 years. Interest is compounded at 4%.
A. Let the amount be 'x' and 1301 - x.
x(1+4/100)^7 = (1301-x)(1+4/100)^9
Solving this we can get 'x'.
Q. A sum of money amounts to Rs.6690 after 3 years and Rs. 10035 after 6 years on CI. Find the sum.
A. P(1+R/100)^3 = 6690 ; P(1+R/100)^6 = 10035
Dividing first eqn by second eqn we get (1+R/100)^3 = 10035/6690 = 3/2
Substituting this value in first equation we get P = 6690 * 2 / 3 = 4460.
Q. A sum doubles itself in 9 years how many will it take to become 8 times.
A. P(1+R/100)^9 = 2P
(1+R/100)^9 = 2
Now finding P(1+R/100)^n = 8P
we need to get (1 + R/100)^n = 8 but 8 = 2^3
(1+R/100)^n = (1 + R/100)^ 9 ^3
we know that A^b^c = A^b*c
so (1+R/100)^n = (1 + R/100)^ 9*3 = (1 + R/100)^27
n = 27
CAT Problems
Q.A sum of money compounded annually becomes Rs.625 in two years and Rs.675 in three years. The rate of interest per annum is
- 7
- 8
- 6
- 5
Ans.b
Quiz
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