Answer:
Thy bought 150 Sweatshirts (x) and 250 tshirts (y)
Explanation:
35x + 25y = 11500
x + y = 400
-25 (x + y = 400) Multiply by -25 to get the y's to disappear when you add the two equations together
-25x - 25y = 10000
35x + 25y = 11500
10x =1500
x = 150
Plug 150 in either equation for x to find y
150 + y = 400
y = 250