Question

a sum of money at simple interest double in 10years .in how many years at the same rate it will be triple

Answer 1

Let x % be the simple interest per annum on Principal amount(P) you deposited.

After 1 year your money will become P + x% P.

After 2 year your money will become P + x%P + x% P.

Similarly, After 6 years your money will become P + 6 (x% P).

Now According to Question, this amount after 6 years is 2 times the amount you deposited i.e P.

Mathematically it can be expressed as,

2P = P + 6 (x% P) ……………(i)

From here, x = 100/6.

Now let’s assume that after n years, your amount gets 4 times the amount you deposited i.e P.

Mathematically it can be expressed as,

4P = P + n (1/6 P) { Since x = 100/6, Therefore x% = 1/6} ………… (ii)

From equation (ii),

n = 18 years.

Just change the values according to the question