Question

In what time would rs.5000 amount to rs.6655 at 10% per annum compounded interest ?

Answer 1

5000(1+10/100)^n=6655
(11/10)^n=6655/5000
(11/10)^n=1331/1000
(11/10)^n=(11/10)³
n=3

Answer 2

The time that would require for Rs. 5000 to Rs. 6655 at a rate of 10% per annum compounded annually is 3 years.

• The formula to find the compound interest is

Compound Interest = $P(1+ \frac{R}{100})^n - P$

• Compound interest =Rs. 6655 , Principal amount = Rs. 5000 , rate of interest = 10%pa.
• Substituting in the formula , we get

6655 = $5000(1+ \frac{10}{100})^n - 5000$

6655 + 5000= 5000 $(1.1)^n$

11655 = 5000 $(1.1)^n$

$(1.1)^n$ = 11655 / 5000

$(1.1)^n$ = 2.331

$(1.1)^n$ = $(1.1)^3$

On comparing both sides , we get

n = 3

• Therefore , the time period is 3 years.