Question

In how many years will ₹ 4000 amount to ₹ 5324 at 10% compound interest?

Answer 1

CI=p {(1+r)^n-1}

5324-4000=4000 {(1+10/100)^n}-4000

5324=4000 (1+1/10)^n

5324/4000=(11/10)^n

1331/1000=(11/10)^n

(11/10)^3=(11/10)^n

n=3  

hence 3 years

Answer 2

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Here's your answer !

Here P = ₹ 4000 = ₹ 5324 and r = 10% p.a.

A = P ( 1 + r/100)n = ₹ 5324 =
₹ 4000 ( 1 + 10/100)n

=> 5324/4000 = (11/10)n

=> (11/10)n = 1331/1000 = (11/10)³

= n = 3

the required time = 3 years.