Use addition or substitution to solve this problem.
To paint his house, Samuel bought 2 cans of paint and one roller for $30. When friends came over to help, he went back to the store and bought three more cans of paint and two more rollers for $50. How much did he pay for a can of paint?

Question

anonymous · Answer

Soo we have :
2x+y=30
3x+2y=50
 
From the first equation you have :
y=30-2x 
you substitute y in the second equation and you get :

3x+2.(30-2x) =50
3x+60-4x=50
-x=-10 or 
x=10
Soo, he paid 10$ for a can of paint