8

Set 3: Linear Equations

Explanation

Answer: A

A rectangle's length is 3 times its width. If the perimeter is 32 cm, what is the width?

A.

4

✓ Correct
B.

16

C.

8

D.

12

Detailed Explanation

Choice A is correct. Choice A is the correct answer. 1. Define variables: Let ww be the width. Then length l=3wl = 3 w. 2. Perimeter formula: P=2l+2wP = 2 l + 2 w 3. Substitute: 32=2(3w)+2w32= 2(3 w) + 2 w 4. Simplify: 32=6w+2w32=8w32= 6 w + 2 w \rightarrow 32 = 8 w 5. Divide by 8: w=4w = 4 6. Verify: Length is 12. 2(12)+2(4)=24+8=322(12) + 2(4) = 24 + 8 = 32 ✓ Choice C is incorrect because this results from 4w=324w = 32 (forgetting to double sides). Choice D is incorrect because this is the length, not the width. Choice B is incorrect because this is half the perimeter.

Key Steps:

The correct answer is 4

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.

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