Answer:
Skiing costs $30 per hour and Boating costs $51 per hour.
Explanation:
Let cost per hour of skiing be x and cost per hour of boating be y. Let's dissect the problem into 2 simultaneous equations.
"John paid $222 for four hours of skiing and two hours boating":

"He paid $213 for two hours skiing and three hours boating":

Now, if we solve for x in the 2nd equation and plug it in the 1st equation, we will have the value for y. Work shown below.

Hence, y = 51
Now, substituting this y value into the 1st equation and solving for x will give us the value of x.

Hence, skiing costs $30 per hour and boating costs $51 per hour.