9
algebra

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

B

$60

C

$50

D

$30

Correct Answer: A

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.

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Linear Functions Set 97