2011 AMC 10B Problem 3

Attempt Problem 3 of the 2011 AMC 10B below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2011 AMC 10B solutions, or check the answer key.

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3.

At a store, when a length is reported as xx inches that means it is at least x0.5x - 0.5 inches and at most x+0.5x + 0.5 inches. Suppose the dimensions of a rectangular tile are reported as 22 inches by 33 inches. In square inches, what is the minimum area for the rectangle?

3.753.75

4.54.5

55

66

8.758.75

Answer: A
Concepts:areaoptimization
Difficulty rating: 770
Solution:

The smallest possible dimensions are 1.5×2.5,1.5\times 2.5, so the area is 1.52.5=3.75.1.5\cdot 2.5=3.75.

Thus, the correct answer is A .

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