Question

A sum of money lent out at simple interest doubled itself in 20 years. in how many years will it triple itself?

Answer 1

Let the sum of money be X
SI=Amount-Principal
In this case, Simple Interest is = X

SI=P*R*T/100
X=X*R*20/100
100x/20x=R
5%=R

Now the X is tripled,
In this case SI=3x-x=2x

SI=P*R*T/100
2x=X*5*T/100
2x/X=T*1/20
2*20=T
40=T

So it will take 40 years to make the sum of money tripled.

Answer 2

Answer:

In 40 years amount will be tripled.

Step-by-step explanation:

let x be the amount

In First Case:

P = x

T = 20 years

A = 2x

SI = 2x - x = x

Using SI formula,

$SI=\frac{P\times R\times T}{100}$

$x=\frac{x\times R\times20}{100}$

R = 100/20 = 5 %

Second Case:

when amount is tripled,

we have A = 3x

P = x

R = 5 %

SI = 3x - x = 2x

We have to find Time , T

$SI=\frac{P\times R\times T}{100}$

$2x=\frac{x\times5\timesT}{100}$

T = (2 × 100) /5

T = 200/5

T = 40 years

Therefore, In 40 years amount will be tripled.