Question

What sum of money should be invested for 5 years at 8% p.a. to earn the same interest as Rs 3600 at 10% p.a. for 4 years?

Answer 1

Since, $P=?,R=8\%p.a.,T=5yrs,P^{\prime }=Rs.3600,R^{\prime }=10\%p.a.,T^{\prime }=4year$

Now$,$ $S.I=S.I^{\prime }$

$\Rightarrow \frac{\left(P\times R\times T\right)}{100}=\frac{\left(P^{\prime }\times R^{\prime }\times T^{\prime }\right)}{100}$

$\Rightarrow \frac{\left(P\times 8\times 5\right)}{100}=\frac{\left(3600\times 10\times 4\right)}{100}$

$\Rightarrow P\times 40=3600\times 40$

$\Rightarrow P=3600$

Hence, $Rs.3600$ should be invested for 5 years at 8% p.a. to earn the same interest as Rs 3600 at 10% p.a. for 4 years.