A sum of money placed at compound interest doubles itself in 8 years.

1.	A sum of money placed at compound interest doubles itself in 8 years. In how many years will it amount to four times itself ?1. 24 years2. 26 years3. 16 years4. 32 years
Answer» Correct Answer - Option 3 : 16 years Given: A sum of money placed at compound interest doubles itself in 8 years. Formula used: A = P(1 + R/100)n where A = amount p = principal R = rate n = time Calculations: Let P be Rs.1, then A = Rs.2 A = P(1 + R/100)n ⇒ 2 = 1(1 + R/100)⁸ ⇒ 4 = 1(1 + R/100)¹⁶ (by squaring both sides) comparing this to A = P(1 + R/100)n we get n = 16 years ∴ the correct answer is 16 years.

A sum of money placed at compound interest doubles itself in 8 years. In how many years will it amount to four times itself ?1. 24 years2. 26 years3. 16 years4. 32 years

Answer» Correct Answer - Option 3 : 16 years

Given:

A sum of money placed at compound interest doubles itself in 8 years.

Formula used:

A = P(1 + R/100)n

where A = amount

p = principal

R = rate

n = time

Calculations:

Let P be Rs.1, then A = Rs.2

A = P(1 + R/100)n

⇒ 2 = 1(1 + R/100)⁸

⇒ 4 = 1(1 + R/100)¹⁶ (by squaring both sides)

comparing this to A = P(1 + R/100)n

we get n = 16 years

∴ the correct answer is 16 years.

Discussion

No Comment Found

Related InterviewSolutions

S.I. on certain sum of money at 5% p.a. for 4 years is Rs. 1,750. What would be C.I. at same rate of interest and for same time period?1. Rs. 1,9002. Rs. 1,885.683. Rs. 1,8854. Rs. 1,880
1/3rd of a principal amount is kept at simple interest in the post office at a rate of 15% per annum, and rest is kept in the bank at compound interest at the rate of 10% per annum. Find the total amount invested if the difference between compound interest and simple interest for two years be Rs. 480.1. Rs 120002. Rs 80003. Rs 40004. Rs 16000
The total sum of amounts of A and B at the end of 4 years and 2 years respectively on the same principal is Rs. 20,020. If A is charged Simple interest at the rate 10% and B is charged Compound interest at the rate 5%. The principal is?1. Rs. 5,0002. Rs. 7,5003. Rs. 2,5004. Rs. 8,0005. Rs. 6,000
A man borrows Rs.21630 on compound interest and return it in three equal year installments. Find the installment charge per year if the rate of 20/3% p.a?1. Rs. 10002. Rs. 9813. Rs. 12004. Rs. 22005. Rs.8192
A laptop is sold for Rs. 1680 cash or for Rs. 1400 cash down payment together with Rs. 287 to be paid after one month. Find the rate of simple interest charged per annum.1. 2.5%2. 3.5%3. 15%4. 30%5. None of these.
Sumit borrowed Rs. 33,000 which has to be paid in three equal installments at simple interest. Calculate the value of annual installment if the rate of interest is 10% per annum.1. Rs. 99002. Rs. 10,0003. Rs. 12,0004. Rs. 14,0005. None of these.
A loan of Rs. 16,550 has to be paid in three equal installments at compound interest. Calculate the value of annual installment if the rate of interest is 10% per annum.1. Rs. 66562. Rs. 12433. Rs. 66554. Rs. 13435. None of these.
Miku borrowed some amount for buying a phone and paid back in two annual installments of Rs. 2646 each, allowing 5% compound interest. What was the amount borrowed?1. 49902. 49503. 49204. 4490
A sum of Rs. 1275 is borrowed at 4% pa compound interest and paid back in 2 equal annual installments. What is the amount of each installment?1. Rs. 6762. Rs. 7003. Rs. 6504. Rs. 5005. Rs. 850
The compound interest on a sum of Rs. 20,000 at 15% p.a. for \(2 \frac{2}{3}\)years, when interest compounded yearly is:1. Rs. 9,0002. Rs. 9,0953. Rs. 9,9084. Rs. 8,896

A sum of money placed at compound interest doubles itself in 8 years. In how many years will it amount to four times itself ?1. 24 years2. 26 years3. 16 years4. 32 years

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment