10
algebra

A phone plan costs $40 per month and includes 2 GB of data. Extra data costs $10 per GB. If you want to spend no more than $70, what is the maximum TOTAL data dd you can use?

A

55 GB

B

33 GB

C

77 GB

D

44 GB

Correct Answer: A

Choice A is the correct answer. Be careful: dd is TOTAL data, not just extra data.

  1. Extra Budget: $70 - $40 = $30 available for extra data.
  2. Extra GB: $30 ÷\div $10/GB = 3 GB extra.
  3. Total Data: 2 GB (included) + 3 GB (extra) = 5 GB.

Alternatively:

  1. Cost Equation: 40+10(d−2)≤7040 + 10(d - 2) \leq 70 (where d≥2d \geq 2)
  2. Solve: 10(d−2)≤3010(d - 2) \leq 30
  3. Divide: d−2≤3d - 2 \leq 3
  4. Add 2: d≤5d \leq 5

?�� Strategic Tip: Always check if the variable represents "total" or "additional" amount.

Choice B is incorrect because 3 GB is the extra data allowed, not total. Choice C is incorrect because it assumes all $70 is for data (70/10=770/10 = 7). Choice D is incorrect because it's a distractor.

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Linear Functions Set 70