Question

One pipe can fill a pool in 20 minutes, a second can fill the pool in 30 minutes, and a third can fill it in 10 minutes. How long would it take the three together to fill the pool?

Answer 1

1/(1/20+1/30+1/10)
=60/11 minutes

Answer 2

How many pounds of birdseed are used to fill each feeder? draw a tape diagram to show your thinking