Question

Help me please............

Answer 1

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.

Answer 2

We can set up a ratio to solve this problem:
15shot        x
5min         12min
We can then cross multiply to get the equation:
180=5x
Divide by 5 to get your answer 
36=x
36 shots in 12 minutes.