Question

A sum of money at simple interest doubles itself in 8 years 4 months. In how much times will it treble itself ?

Answer 1

Let the sum be Rs. x. Then, amount = Rs 2x
∴ SI = Rs (2x - x) = Rs x
         Time = 8 whole 4/12 years = 25/3 years
Thus, P = Rs x, SI = Rs x and T = 25/3 years
∴rate = 100*SI/P*T = (100*x/x *3/5) % p.a. = 12% p.a.

Again, sum = Rs x, amount = Rs 3x and rate = 12% p.a.

Then, SI= Rs (3x-x) = Rs 2x
∴P= Rs x, SI = Rs 2x and R = 12% p.a.
∴ Time = 100*SI/P*R
= (100*2x/x*12) years = 50/2 years = 16 years and 8 months.


Hence, the sum will treble itself in 16 years and 8 months

Answer 2

Hope it will help you