Final answer:
To solve the inequality 100 - 2x < 40, you subtract 100 from both sides and divide by -2, which gives x > 30. This means Gloria can purchase more than 30 school lunches while staying under her $100 budget and having less than $40 leftover.
Step-by-step explanation:
The inequality 100 - 2x < 40 represents the condition where Gloria wishes to ensure she has less than $40 remaining after buying school lunches. To solve for x, which represents the number of lunches Gloria can purchase, we start by subtracting 100 from both sides of the inequality:
100 - 100 - 2x < 40 - 100
-2x < -60
Next, we divide both sides by -2, remembering to reverse the inequality because we are dividing by a negative number:
-2x / -2 > -60 / -2
x > 30
Thus, the correct answer is x should be greater than 30 lunches to stay within her budget, that is, Gloria can buy more than 30 school lunches and still have less than $40 remaining.