Another Question from Kiasuparents

In class 5A, there were 1/2 as many girls as boys. In class 5B , there were 1/3 as many boys as girls. The number of boys in class 5B was 2/3 as many as the number of girls in class 5A. There were 32 pupils in class 5B.

A) express the number of pupils in 5B as a fraction of the number of pupils in 5A

B) after some boys were transferred from 5A to 5B , there were 1/2 as many of 5B boys as the number of 5B girls. How many pupils were there in class 5B after the transfer ?

Solution:

5B: Boys : Girls = 1 :3 so 4units -> 32, 1unit -> 8. Boys is 8 and girls is 24
5B Boys : 5A girls = 2:3, so 5A girls is 12
5A boys: 12x2=24 
5A total pupils is 36

A) 32/36=8/9

B) After transfer
No. of 5B girls remains the same -> 24
No. of 5B boys --> half of 5B girls -> 12
Total no. of pupils in 5B -> 24 + 12 = 36