Math problem please help

A student bake sale is selling baked goods. In total they sell 100 pieces of baking, Chocolate chip cookies sell for $0.50 and Muffins for $1.25. The total money earned from the bake sale came to 68.75. How many muffins did they sell?

.50×75=37.5

1.25×25= 31.25

37.5+31.25=68.75