Question

A certain sum amounts to Rs. 5,292 in two years and Rs. 5,556.60 in three years, interest being compounded annually. Find the original sum

• A. Rs. 7000
• B. Rs. 6200
• C. Rs. 5600
• D. Rs. 4800

Answer 1

The correct option is D Rs. 4800

Sum after 2 years$=Rs.5292$

Sum after 3 years $=Rs.5556.60$

Interest for onr year $=5556.60-5292=Rs.264.60$

C.I for 1 year=S.I for 1 year

$Interest=\frac{PRT}{100}$

$\Rightarrow 264.60=\frac{5292\times R\times 1}{100}$

$\Rightarrow R=\frac{264.60\times 100}{5292}=5$%

Let the sum$=Rs.x$

Amount $=Rs.5292,$ Time 2 years, $R=5$%

$Amount=P{(1+\frac{R}{100})}^t$

$\Rightarrow 5292=x{(1+\frac{5}{100})}^2$

$\Rightarrow 5292=x\times \frac{105}{100}\times \frac{105}{100}$

$\Rightarrow x=\frac{5292\times 100\times 100}{105\times 105}=Rs.4800$