Answer:
40%
Explanation:
The total number of students are '20'. Moreover the number of boys out of that 20 students are '8'.
So to find the percentage of the number of boys, take 8 (number of boys) divided by 20 (the total) and times that by 100, which will give you the percentage.
This is how it goes...
× 100 = 40%
∴ 40% of the class is made up of boys.