Question

In how many years will rate of simple interest money double itself at 8%per annum?

Answer 1

We know that
Amount = p*r*t/100 +p
Amount is double of principle
Let principal is x then amount is 2x
Therefore let time is the and rate is 8%
Amount= x * 8* t/100 +x
2x = x (8 t /100 + 1)
2 -1 = 8t /100
100= 8t
T = 100/8
T = 12.50 years
Time taken for double of principle is 12year and 6 month

Answer 2

Let principal = x, then the Amount = 2x.

So, Interest = Amount - Principal

                    = 2x - x

                   = x.


We know that SI = PRT/100

                        x = (x * 8 * T)/100

                       100x = 8x * T

                       100x/8x = T

                       12.5 = T.


Therefore the time has taken = 12.5 years.


Hope this helps!