a police officer pulls over 3 men for speeding

a police officer pulls over 3 men for speeding and he said that he would let them go if their dick sizes added up to 15 inches. so the first guy pulled down his pants and his was 7 inches, the second guy pulled down his pants and his was 6 inches, and the third guy pulled down his pants and his was 2 inches. after the cop left... the third guy said, "gee its a good thing i had a boner!"