10

Set 13: Linear Functions

Explanation

Answer: A

A runner starts at the 10-mile marker and runs toward the finish line at 6 mph. Another runner starts at the 0-mile marker and runs at 8 mph. When does the second runner catch the first?

A.

55 hours

✓ Correct
B.

22 hours

C.

44 hours

D.

1010 hours

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Relative speed. 1. Runner 1: d=6t+10d = 6 t + 10. 2. Runner 2: d=8td = 8 t. 3. Equate: 8t=6t+108t = 6 t + 10. 4. Solve: 2t=10t=52t = 10 \rightarrow t = 5. Strategic Tip: Gap (10) divided by Speed Difference (2) = Time (5). Choice B is incorrect. Choice C is incorrect. Choice D is incorrect.

Key Steps:

The correct answer is 55 hours

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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