Question

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

Answer 1

Answer:

let the time be x

time = 2 years

Answer 2

Given:

A sum of money at simple interest doubles itself in 8 years 4 months.

To Find:

Time when it will treble itself.

Solution:

Let the sum of money be ₹x.

Then amount=₹2x.

Therefore, SI=₹(2x-x)=₹x.

Time=$8\dfrac{4}{12}$years.

=$\dfrac{25}{3}$ years.

Therefore,rate=$\dfrac{100\times SI}{P\times T}$

=$(\dfrac{100\times x}{x}\times\dfrac{3}{25})$%p.a

=12%p.a

Again, sum=₹x,

amount=₹3x

rate=12%p.a

Then,SI=₹(3x-x)=₹2x

Therefore,P=₹x,SI=₹2x and R=12%p.a

Time=$\dfrac{100\times2x}{x\times12}years=\dfrac{50}{3} years$

=16 years 8 months.

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