Question

At 25 percent per annum interest in how many years the simple interest on a sum of money treble itself?

Answer 1

put that principal =100
then R = 25%
triple principal of many years so
principal+interest= 300
100+interest= 300
then interest= 200
now
200=(100*t*25)÷100
t= (200*100)÷(100*25)
t= 8 years
means in 8 years principal is trible

Answer 2

Answer: It takes 8 years to treble the sum of money at 25% p.a.

Step-by-step explanation:

Let the principal amount be 'P'.

Rate of interest = 25% p.a.

Amount becomes triple i.e. 3P.

So, Interest becomes

$I=A-P\\\\I=3P-P\\\\I=2P$

So, using the "Simple interest ":

$I=\dfrac{P\times R\times T}{100}\\\\2P=\dfrac{P\times 25\times T}{100}\\\\2=\dfrac{T}{4}\\\\T=2\times 4=8\ years$

Hence, it takes 8 years to treble the sum of money at 25% p.a.