Answer:
a) 5x + 7y ≥ 1200
b) No.
c) A minimum of 114 plain t-shirts.
Step-by-step explanation:
Given information:
Define the variables:
The inequality to represent the given information using the defined variables is:
Substitute x = 150 and y = 60 into the inequality:
⇒ 5(150) + 7(60) ≥ 1200
⇒ 750 + 420 ≥ 1200
⇒ 1170 ≥ 1200
As 1170 is not greater than or equal to 1200, John will not be able to cover the product costs if he sells 150 plain shirts and 60 graphic shirts.
Substitute y = 90 into the inequality and solve for x:
⇒ 5x + 7(90) ≥ 1200
⇒ 5x + 630 ≥ 1200
⇒ 5x + 630 - 630 ≥ 1200 - 630
⇒ 5x ≥ 570
⇒ 5x ÷ 5 ≥ 570 ÷ 5
⇒ x ≥ 114
Therefore, if John sells 90 graphic t-shirts, he must sell a minimum of 114 plain t-shirts to break even.