7

Set 14: Linear Functions (Intermediate)

Explanation

Answer: A

A plumber charges a flat fee plus an hourly rate. 2 hours cost $140. 5 hours cost $260. What is the hourly rate?

A.

$40

✓ Correct
B.

$60

C.

$50

D.

$30

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Calculate slope. 1. Points: (2,140)(2, 140) and (5,260)(5, 260). 2. Slope: 260−1405−2=1203=40\frac{260 - 140}{5 - 2} = \frac{120}{3} = 40. 3. Context: Slope is cost per hour. Strategic Tip: Rate = Change in Cost / Change in Time. Choice B is incorrect because flat fee. Choice C is incorrect. Choice D is incorrect.

Key Steps:

•

The correct answer is $40

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.
← PreviousNext →

🎯 Keep Practicing!

Master all sections for your best SAT score

📚Reading & Writing→📖Vocabulary→