Answer:
7 shirts
Step-by-step explanation:
The function for producing shirts is
f($) = 50 + 7.5(x), where x is the number of shirt
The function for selling shirts is
f($) = 15(x)
For there to be a profit, he must make more money selling the shirts than he spent on making the shirts
Therefore, 15(x) > 50 + 7.5(x)
15x > 50 + 7.5x
15x - 7.5x > 50
7.5x > 50
x > 6.67 shirts
To make a profit, Juan must sell at least 7 shirts
