2004 AMC 10B Problem 5

Attempt Problem 5 of the 2004 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 2004 AMC 10B solutions, or check the answer key.

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5.

In the expression cabd,c \cdot a^b - d, the values of a,b,c,a, b, c, and dd are 0,1,2,0, 1, 2, and 3,3, although not necessarily in that order. What is the maximum possible value of the result?

55

66

88

99

1010

Answer: D
Concepts:exponentoptimizationcasework
Difficulty rating: 1120
Solution:

Setting d=0d = 0 removes the subtraction, so we maximize cabc \cdot a^b using 1,2,3.1, 2, 3.

Taking c=1,c = 1, a=3,a = 3, b=2b = 2 gives 32=9.3^2 = 9. The alternative 23=82^3 = 8 is smaller, and any assignment with c>1c \gt 1 forces a smaller power. The maximum is 9.9.

Thus, the correct answer is D.

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