Question

The ratio of boys to girls in a group is 7:1. If there are 66 more boys than girls, work out how many girls there are

Answer 1

Answer:11

Step-by-step explanation:

Boys : girls=7:1

Sum of ratio=7+1=8

Let them number of girls be y

Then they number of boys=y+66

Total number of pupils=y+y+66

Total number of pupils=2y+66

Number of girls=(girls ratio)/(sum of ratio) x (total number of pupils)

y=1/8 x (2y+66)

Cross multiply

y x 8=2y + 66

8y=2y + 66

Collect like terms

8y-2y=66

6y=66

Divide both sides by 6

6y/6=66/6

y=11

The number of girls is 11