5
algebra

A rectangle's length is 4 cm more than its width. The perimeter is 40 cm. What is the width?

A

12

B

8

C

16

D

10

Correct Answer: B

Choice Bhoice D is the correct answer.

  1. Define: Width = ww, Length = w+4w + 4.
  2. Perimeter: 2(w+4)+2w=402(w + 4) + 2w = 40
  3. Simplify: 2w+8+2w=40→4w+8=402w + 8 + 2w = 40 \rightarrow 4w + 8 = 40
  4. Subtract 8: 4w=324w = 32
  5. Divide by 4: w=8w = 8
  6. Verify: Length 12. 2(12)+2(8)=24+16=402(12) + 2(8) = 24 + 16 = 40 ✓

Choice Bhoice A is incorrect because this is the length.

Choice Bhoice D is incorrect because calculation error.

Choice Bhoice C is incorrect because calculation error.

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Linear Functions Set 29