John can make a profit of $7 per chair and $12 per desk. He has at most 48 hrs working time available. It takes 3 hrs to make a chair and 2 hrs to make a desk. Write the objective function and constraints necessary to determine how many chairs and desks he should make to maximize profit.

Help please!!!

X=Chairs

Y=desks

I cant figure out the constraints other than:

3x+2y<48

7x+12y>0

x>0

y>0