Question

What is the answer to this word problem or how would I solve it

Answer 1

Its a simultaneous equation:
lets make "x" the used games and "y" the new ones

4x + 2y = 84
6x + y = 78. (multiply this by 2 to cancel out y)
12x + 2y = 156

so now we subtract them:
12x - 4x = 156 - 84
x = 9
used games cost $9
new games cost 78 - 6(9) = $24

Janet has $120 but she already bought 3 NEW games so:
120 - 3(24) = $48 left

48/9 = how many used ones she can buy = 5. something

she can buy 5 used