Well, if he shoots 15 shots in 5 minutes then that means he shoots 3 per minute.
3 x 12 = 36
In 12 minutes, he will have shot 36 shots.
Well a percent is always a number/100 (3%=3/100)
So what you have to do is put 66.6 over 100 and get
66.6/100 as your answer.