Question

The ratio of the boys to girls in a class is 2 : 3. If 20% of boys leave this class, then the new ratio of boys to girls is

• A. 8 : 15
• B. 8 : 3
• C. 3 : 7
• D. 4 : 7

Answer 1

The correct option is A 8 : 15

Let the total number of students=100
Ratio of boys and girls=2:3
$2+3=5$
No. of boys =$\frac{2}{5}\times 100=40$
No. of girls=$\frac{3}{5}\times 100=60$
If 20% of the boys leaves the class then 20% of 40
$\frac{20}{100}\times 40=8$
Now number of boys=$40-8=32$
New ratio=$32:60\Rightarrow 8:15$