Answer:
Each bought 2 shirts.
Step-by-step explanation:
Number of Shirts Bought by Erin = X
Number of Shirts Bought by Dan = Y
Price of Erin Shirt = $12
Price of Dan Shirt = $18
Spending by Erin = $12X + $18
Spending by Dan = $16Y + $10
As given in Question
Spending by Erin = Spending by Dan
$12X + $18 = $16Y + $10
$12X + $18 = $16X + $10 (Dan bought same Number of Shirt as Erin)
16X - 12X = $18 - $10
4X = 8
X = 8/4
X = 2
Each bought 2 shirts.