Discussion Forum

1)

A sum of money amounts to Rs. 5,200 in 5 years and to Rs. 5,680 in 7 years at simple interest. The rate of interest per annum is

 

Answer:

Option D

Explanation:

$P+S.I.$ for $5$ years $=5,200$ ---(1)

$P+S.I.$ for $7$ years $=5,680$ ---(2)

(2) - (1) $\Rightarrow S.I.$ for $2$ years $=480$

$S.I.$ for $1$ year $=240$

From equation (1)

$P+5\times 240$ $=5200$ $\Rightarrow P$ $=5200-1200$ = Rs. $4000$

$R$ $=\frac{100\times SI}{P\times N}$ $=\frac{100\times 240}{1\times 4000}$ = 6%.