If they have one hour remaining on the trip, how many crates will they package?

Question

During a community service event, Andre and Deandre are packaging cans of food into boxes and every 4 boxes are loaded into a crate. Each box holds 40 cans. The boys are able to fill and seal a box every 45 seconds. 

Answer 1

1 hour=60min=3600sec so 3600/45sec per box=80 boxes. 4 boxes in a crate so 80/4=20 crates