Can you think outside the box to solve this problem?

It is so easy to get into a rut when solving problems. Ask a typical elementary school student how many apples you have if you take 8 apples from 12 apples and the knee jerk reaction is 4 apples.

Here is a not so typical looking problem involving 3 variables:
2x+5y+z=120
3x+2y+3z=120
x+6y+z=120

That all equations equal 120 should alert you that there might be a shortcut for solving them. There is something else all three equations have in common that allows for a solution by doing a single simple calculation.