A certain sum was invested at a certain rate at simple interest. It took 8 years to quadruple the sum. Find the time it would take to become 10 times itself (in years).

Options

A. 18
B. 24
C. 36
D. 30

Answer

B

Explanation

Let the sum be Rs. P.
It amounted to Rs. 4P in 8 years.
S.I. for 8 years = Rs. 3P.
Let the rate of interest be R% per annum
`3P=((P)(8)(R ))/(100)`
`R=(75)/(2)`
To become 10 times itself, S.I. must be Rs. 9P.
Let the required time be t years.
`9P=((P)(t)((75)/(2)))/(100)implies t=24`.