If you deposit $5000 today at 15% interest rate, in how many years will the amount grow to 60000

Question

There is 60% increase in an amount in 6 years at simple interest.
What will be the compound interest of Rs. 12000 after 4 years at the same rate?

Answer 1

Assuming interest is compounding -

P = 5000
r = 15
T= ?
M=60,000

M = P (1 + r/100)^T
60000 = 5000 (1 + 15/100)^T
12 = (1.15) ^ T

T = 17.8 (approx) i.e. 17 years and 9 months