Alice was folding laundry. She folded 20 shirts from 7:20 to 7:25. When she finishes folding all the shirts, she was done. (a) If she folded shirts at 7:15 and ended at 7:38, estimate how many shirts she would have folded in all. Explain your reasoning. (b) Write an equation to represent how many shirts Alice has left to fold if she started at 7:15. Explain your reasoning.