Question

in a class there are 50students the average Age of girls is 12.3years and average age of boys is 12.5years the average age of class is 12.42 then the numbers

Answer 1

Answer

Number of boys and girls in the class are 30 and 20 respectively.

Explanation

Suppose number of boys in the class are x, then number of girls in the class will be 50-x.

Formula of average = Sum of ages/total number

sum of ages of boys = 12.5x

sum of ages of girls = 12.3(50-x) = 615 - 12.3x

average age of whole class = {12.5x + 615 - 12.3x} / 50 = 12.42

Now, solve the equation to find x

0.2x + 615 / 50 = 12.42

0.2x + 615 = 621

0.2x = 621 - 615

0.2x = 6

x = 6/0.2

x = 30

so no of boys = x = 30

no of girls = 50 - x = 50 - 30 = 20