10
algebra

A rectangle's length is 2 cm less than 3 times its width. The perimeter is 36 cm. What is the length?

A

5

B

13

C

15

D

10

Correct Answer: B

Choice Bhoice C is the correct answer.

  1. Define: Width = ww, Length = 3w−23w - 2.
  2. Perimeter: 2(3w−2)+2w=362(3w - 2) + 2w = 36
  3. Simplify: 6w−4+2w=36→8w=406w - 4 + 2w = 36 \rightarrow 8w = 40
  4. Divide by 8: w=5w = 5
  5. Length: 3(5)−2=133(5) - 2 = 13
  6. Verify: 2(13)+2(5)=26+10=362(13) + 2(5) = 26 + 10 = 36 ✓

Choice Bhoice C is incorrect because this is the width.

Choice Bhoice D is incorrect because calculation error.

Choice Bhoice A is incorrect because calculation error.

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Linear Functions Set 30