Answer: Supergirl = 19 and Wonder Woman = 8
Explanation:
Let g represent the quantity of Supergirl keychains and w represent the quantity of Wonder Woman keychains.
Qty Cost
Supergirl g $3g
Wonder Woman w $2w
Total 27 $73
Qty: g + w = 27 → -2(g + w = 27) → -2g - 2w = -54
Cost: 3g + 2w = 73 → 1(3g + 2w = 73) → 3g + 2w = 73
g = 19
Input g = 19 into one of the original equations to solve for w:
g + w = 27
(19) + w = 27
w = 8