2008 AMC 12A Problem 8

Below is the professionally curated solution for Problem 8 of the 2008 AMC 12A, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2008 AMC 12A solutions, or check the answer key.

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Concepts:cube geometrysurface areavolume

Difficulty rating: 1380

8.

What is the volume of a cube whose surface area is twice that of a cube with volume 1?1?

2\sqrt{2}

22

222\sqrt{2}

44

88

Solution:

The cube with volume 11 has side 11 and surface area 6.6. The larger cube has surface area 12,12, so if its side is s,s, then 6s2=12,6s^2 = 12, giving s=2.s = \sqrt{2}.

Its volume is (2)3=22. (\sqrt{2})^3 = 2\sqrt{2}.

Thus, C is the correct answer.

Problem 8 in Other Years