Let's begin by listing out the information given to us:
Let Gina and George's bonuses = x
Gina received 3 bonus checks = 3x
Gina bought a t-shirt = 3x - 8
George received 2 bonus checks = 2x
George received an extra $15 = 2x + 15
Gina and George currently have the same amount of money, that means:
3x - 8 = 2x + 15
Put like terms together (add 8 to both sides & subtract 2x from both sides)
3x - 2x - 8 + 8 = 2x - 2x + 15 + 8
x = 23
x = $23
Each bonus check is $23