**Brothers in Arms wrote:**Q2:

On a bus,there were 3/4 as many children as adults.After two adults had alighted from the bus,the number of children became 4/5 as the number of adults. How many children were there in the bus?

Could someone please explain to me the solution:

At first why children and adults must times 4?

Thank you!

This question is about the number of children (before and after) remained unchanged. We therefore attempt to make the unit size of the model the same by equating the

**CHILDREN**
__Before__
C : 3u => 12u (x4)

A: 4u => 16u (x4)

__After__
C : 4u => 12u (x3)

A: 5u => 15u (x3)

You can then figure out that 1u => 2

Number of children = 24.