Correct Answer - Option 1 : 8
Formula Used :
For compound interest
A = P(1 + R/100)n
where P → Principal Amount
A → Final Amount
R→ Interest rate
n → Time Period
Given:
Sum of amount at a certain rate of compound interest double in 3 years
∴ A = P(1 + R/100)n
⇒ 2P = P (1 + R/100)3
⇒ 2 = (1 + R/100)3
Now, In 9 years amount will be k times of the original principal
⇒ kP = P(1 + R/100)9
⇒ kP = P{(1 + R/100)3}3
⇒ kP = P(2)3 = 8 × P
⇒ k = 8
∴ The value of k is 8