Only answer if you can answer fully and correctly pls

The valid solution is (35, 5)
The earning constraint is 25x + 15y ≥ 900
The time constraint is x + y ≤ 40

In order to find all of these you need to start with the equations. 

Let x = hours tutoring and y = referee hours. 

We know that when we add them together we can work at the most 40 hours; this gives us the time constraint. We also know that we need to make at least 900. So if we multiply the hours worked by the amount that we make, we should get more than that; this gives us the earning constraint. 

The last piece we need is the valid solution. We know we need an ordered pair for this. However, only one of them works with the time constraint. So we must use that one. 

121 pints. they had 176 and drank 55