Question

In a case of 42 students, the no. of boys is 2/5 of the girls .find the no. of boys and girls in the class​

Answer 1

Answer:

If 2/5 are boys then 3/5 are girls

These added together equal 5/5 which is the total number in the class ( 45 in this example )

45 divided by 5 equals 9

3 fifths would be 3 x 9 = 27 girls

The other way is to let x = number of girls

multiply 45 ( total # students) by (3/5)

x = 45 (3/5)

x = 135/5 = 27 girls

Answer 2

Answer:

No: of girls = 30

No: of boys = 12

Explanation:

Let the no of boys be 'x'

Let the no of girls be 'y'

Given that total number of students = 42

x+y=42

Also Given

x=(2/5)y

x=2y/5

(2y/5)+y = 42

(2y+5y)/5 = 42

7y/5 = 42

7y = 42 x 5

y = 210/7

y=30

Therefore No: of girls = 30

No of boys = Total students - No of girls

No of boys = 42-30

Number of boys = 12