Question:
Tick (✓) the correct answer:
Number of boys and girls in a class are in the ratio 7 : 5. The number of boys is 8 more than the number of girls. The total class strength is
(a) 56
(b) 52
(c) 48
(d) 36
Solution:
(c) 48
Let the number of boys in the class be $\mathrm{x}$.
Then, the number of girls will be $(\mathrm{x}-8)$.
The equation becomes:
$\frac{x}{x-8}=\frac{7}{5}$
$\Rightarrow 5 x=7 x-56$
$\Rightarrow 5 x-7 x=-56$
$\Rightarrow-2 x=-56$
$\Rightarrow x=\frac{-56}{-2}=28$
Therefore, the number of boys is 28 .
Number of girls $=(\mathrm{x}-8)=28-8=20$
Total strength of the class $=28+20=48$