A house has a large window made of 15 equal-sized pieces of glass, each the same size and shape. There are 3 pieces of glass that are cracked. If a rock thrown by a lawn mower hits the window, what is the probability that the rock hits a piece of glass that is cracked?
The probability is 1/5. You put the pieces of glass that are cracked, 3, over the total amount of glass, 15. That's the fraction 3/15, which you can simplify to 1/5.
