Yuri O. answered 02/19/21
16 years online, 464 former SAT problems drilled down
t - number of t-shirt sold
h - number of hats sold
10t - money earned for sale of t-shirts
15h - money earned for sale of hats
Writing the system of equations:
10t + 15h = 1140
t + h = 95 → multiply by "-10" and then add equations
10t + 15h = 1140
-10t - 10h = 950
5h = 190
h = 38
Calculating "t":
t = 95 - h = 95 - 38 = 57
Checking:
10 • 57 + 15 • 38 = 1140
1140 = 1140 ← worked out!