Let Mark's weight be x and Jose's weight be y.
1) x+y=270
We also know that Mark weighs 30 pounds less than twice Jose's weight, giving us
2) x+30=2y
Using 1), isolate for a variable.
3) y=270-x
Plug 3) back into 2) to solve for x.
x+30=2(270-x)
x+30=540-2x
3x=510
x=170 lbs.
Using x, plug that back into 1) to solve for Jose's weight.
170+y=270
y=100 lbs.
Therefore, Mark weighs 170 pounds and Jose weighs 100 pounds.
