This is a case of simultaneous equations. We expand the equations
2(x + y) = 600 | eqn 1
3(x - y) = 600 | eqn 2
Expanding,
2x + 2y = 600 | eqn 3
3x - 3y = 600 | eqn 4
We employ the elimination method. That way we multiply eqn3 by 3 and eqn 4 by 2
Hence, we get
6x + 6y = 1800 | eqn 4
6x - 6y = 1200 | eqn 6
Next, we add eqns 4 and 6, we get
12x = 3000 | dividing both sides by 12
x=3000/12 = 250
We then substitute this value of x into eqn 1 to get
2(250) + 2y = 600
500 + 2y = 600 | minus 500 from both sides to get
2y = 600 - 500
2y = 100 | Dividing both sides by 2, we get
y = 100/2 = 50
Therefore, x = 250, y = 50