Question

Monica has $20. She needs to buy a gallon of milk that costs $2.50. She also wants to buy yogurt, which costs $1.20 a cup. Which inequality can you use to find the number of cups of yogurt Monica can buy?
1.20x + 2.5 Greater-than-or-equal-to 20
1.20x + 2.5 Less-than-or-equal-to 20
1.20x + 2.5 < 20
1.20x + 2.5 > 20

Answer 1

You want the total cost to be no more than $20, so:
1.20x + 2.50 ≤ 20

If x must be a whole number of cups, x ≤ (20 − 2.50)/1.20 = 17.50/1.20 ≈ 14.58, so she can buy at most 14 cups.