Solutions:
we are given that Fred the clown can create 20 animal balloons every 15 minutes.
It mean that Fred the clown can create
baloons every minutes.
In 6 hr and 45 minutes, we have a total of

So total number of balloons created can be found by multiplying the number of ballons created in one minutes by total number of available minutes.
So number of balloons created

It mean that Fred can create 540 balloons in 6 Hrs and 45 minutes.