Peeling Potatoes

Annie and Steve were assigned kitchen duty at camp. Annie peels 5 potatoes a minute and Steve can peel 3 potatoes per minute.

Steve gets a 4-minute head start, and then they continue peeling together until they have finished the pile. If they each peel the same number of potatoes, how many potatoes were there when they started?

Extra: What if Steve had a 5-minute head start? Discuss what happens in this situation.

hands peeling 
a potato