Question

a sum of money lent out at simple interest Doubles itself in 8 years,
find:
i) the rate of interest
ii) in how many years will the sum become triple of itself at the same rate percent.

Answer 1

Let principal deposited be x, since amount is double interest will also be x now,
SI=100*x divided by (8*x)=12.5

Answer 2

Let principal be x. If principal is x , then A=2x ,si=2x-x=x. R= 100*si/p*t

R= 100 * x/x*8=12.5

Second

Let p be x so,A=3x,SI=2x

T=2*100/x* 12.5=16 years