Answer:
15n + 45 ≤ 120
n ≤ 5
She can buy up to 5 balloons.
Explanation:
Fixed amount: $45
Amount per balloon: $15
Let n = number of balloons
Total expense: maximum of $120, which means less than or wequal to $120
15n + 45 ≤ 120
15n ≤ 75
n ≤ 5
She can buy up to 5 balloons.