Question

A sum of money lent at simple interest amounts to $Rs783$ in $2$ years and to $Rs837$ in $3$ years. Find the sum and the rate per cent annum.

Answer 1

Amount after $2$ years $=Rs.783$

Amount after $3$ years $=Rs.837$

Therefore,

S.I. of $1$ year $=837-783=Rs.54$

$\Rightarrow$ S.I. of $2$ years $=54\times 2=Rs.108$

Principal sum $=783-108=Rs.675$

Therefore,

$S.I.=\frac{PRt}{100}$

$\Rightarrow 54=\frac{675\times R\times 1}{100}$

$\Rightarrow R=\frac{54\times 100}{675}=8\%$