The average marks of boys in a class is 52 and that of girls is 42. The average marks of boys and girls combined is 50. The percentage of boys in the class is

Question

The average marks of boys in a class is 52 and that of girls is 42. The average marks of boys and girls combined is 50. The percentage of boys in the class is (A) 40 (B) 20 (C) 80 (D) 60

Tardigrade Admin · Accepted Answer

52x + 42y = 50 (x + y) 2x=8y ⇒ (x/y)=(4/1) and (x/x+y)=(4/5) ∴ % of boys = 80.

Q. The average marks of boys in a class is $52$ and that of girls is $42$ . The average marks of boys and girls combined is $50$ . The percentage of boys in the class is

$40$

$20$

$80$

$60$

$52 x + 42 y = 50 (x + y)$
$2 x = 8 y$
$\Rightarrow \frac{x}{y} = \frac{4}{1}$ and $\frac{x}{x + y} = \frac{4}{5}$
$∴ % o f b oys = 80.$

Q. The average marks of boys in a class is 52 and that of girls is 42. The average marks of boys and girls combined is 50. The percentage of boys in the class is

40

20

80

60