Juan is making t-shirts to sell at a concert. The cost of making the shirts is $50 plus $7.50 per t-shirt.

He will sell them for $15 each.

What is the minimum number of t-shirts he must sell to make a profit?

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

final answer is : )