Multiple choice

The width of a rectangular park is increased by 25%. By what percentage should the length be decreased to maintain the same area?

  1. 10%

  2. 15%

  3. 20%

  4. 40%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If width W increases by 25% (1.25W), the new length L' must satisfy 1.25W * L' = W * L. Thus L' = L / 1.25 = 0.8L. A reduction from L to 0.8L is a 20% decrease.

AI explanation

Area is the product of length and width, so let the initial dimensions be 1 and 1, giving an area of 1. The new width is 1.25, so to maintain the area of 1, the new length must be 1 / 1.25 = 0.8. The length decreases from 1 to 0.8, which is a 20% decrease. The result is 20%.

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