10

Set 11: Linear Inequalities

Explanation

Answer: A

A data plan allows a maximum of 15 GB per month. After using 8.5 GB, which inequality represents the remaining data dd that can be used?

A.

d6.5d \leq 6.5

✓ Correct
B.

d6.5d \geq 6.5

C.

d23.5d \leq 23.5

D.

d+8.515d + 8.5 \geq 15

Detailed Explanation

Choice A is correct. Choice A is the correct answer. This real-world constraint problem models resource allocation with inequalities. 1. Total usage: 8.5+d8.5+ d must not exceed 15 GB 2. Set up: 8.5+d158.5+ d \leq 15 3. Solve: Subtract 8.5: d158.5d \leq 15 - 8.5 4. Calculate: d6.5d \leq 6.5 GB Strategic Tip: Maximum capacity problems use \leq to ensure totals don't exceed limits. Choice B is incorrect because 6.5\geq 6.5 would mean using at least 6.5 GB more, which could exceed the 15 GB limit. Choice C is incorrect because it adds 8.5 and 15 instead of subtracting, misunderstanding the constraint. Choice D is incorrect because while structurally close, using \geq reverses the constraint logic.

Key Steps:

The correct answer is d6.5d \leq 6.5

Why others are wrong:
B: Choice B is incorrect and may result from a calculation error.
C: Choice C is incorrect and may result from a calculation error.
D: Choice D is incorrect and may result from a calculation error.

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