Question

a sum of money doubles itself in 3 yrs at a simple interest. In how many yrs will it amount to 8 times itself?

Answer 1

Answer:

21 years

Step-by-step explanation:

Simple Interest= (Principal x Rate x Time)/100

If an amount doubles itself, Interest= Principal.

Also, if an amount becomes 8x Principal, Interest alone= 7x Principal.

The Rate of Interest remains the same for both cases.

For double the Principal,

Principal= (Principal x Rate x 3)/100

Thus, Rate= 100/3

Using the same rate, we can find the time for getting 8x the Principal.

(7x Principal)= (Principal x 100/3 x Time)/100

Solving the equation, we get time= 21 years.