In how many years will ₹ 7000 amount to ₹ 9317 at 10 per cent per annum compound interest ?

Given,

P = ₹ 7000

A = ₹ 9317

r = 10%

Let in n years ₹ 7000 amount to ₹ 9317.

By formula,

A = $P\Big(1 + \dfrac{r}{100}\Big)^n$

Substituting values we get :

$\Rightarrow 9317 = 7000 \times \Big(1 + \dfrac{10}{100}\Big)^n \\[1em] \Rightarrow \dfrac{9317}{7000} = \Big(\dfrac{110}{100}\Big)^n \\[1em] \Rightarrow \dfrac{1331}{1000} = \Big(\dfrac{11}{10}\Big)^n \\[1em] \Rightarrow \Big(\dfrac{11}{10}\Big)^3 = \Big(\dfrac{11}{10}\Big)^n \\[1em] \Rightarrow n = 3.$

Hence, in 3 years ₹ 7000 amounts to ₹ 9317 at 10 percent compound interest.