Final answer:
The inequality that represents the amount of additional groceries needed is g ≥ 45, meaning at least $45 worth of groceries must still be purchased to reach the $100 requirement.
Step-by-step explanation:
To solve the problem, we need to write an inequality that represents the amount of groceries, g, that the person still needs to buy. The student already has $55 worth of groceries in the cart, and they need to have at least $100 worth of groceries to feed every guest at the party. The inequality would be:
55 + g ≥ 100
We can now solve the inequality for g to find out how much more needs to be spent:
g ≥ 100 - 55
g ≥ 45
Therefore, the person needs to buy at least $45 worth of additional groceries to meet the minimum requirement of $100.