Question

A certain sum at simple interest amounts to Rs. $1350$ in $5$ years and to Rs. $1620$ in $8$ years. What is the sum?

• A. Rs. $700$
• B. Rs. $800$
• C. Rs. $900$
• D. Rs. $1000$

Answer 1

The correct option is C Rs. $900$

According to question, we have

$P+\frac{P\times r\times 8}{100}=1620$ ......(i)
$P+\frac{P\times r\times 5}{100}=1350$ ......(ii)
Taking difference of both gives

$(P+\frac{8Pr}{100})-(P+\frac{5Pr}{100})=1620-1350$
$\Rightarrow \frac{3Pr}{100}=270$
$\Rightarrow \frac{Pr}{100}=90$
Substituting this value in equation (i), we get
$P+90\times 8=1620$
$\Rightarrow P=900$

Therefore, the sum is Rs. $900$.