2004 AMC 12B Problem 2

Below is the professionally curated solution for Problem 2 of the 2004 AMC 12B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2004 AMC 12B solutions, or check the answer key.

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Concepts:optimizationcasework

Difficulty rating: 1000

2.

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

Solution:

To maximize, set d=0.d = 0. With a,b,ca, b, c taking 1,2,3,1, 2, 3, the term cabc \cdot a^b is largest when c=1c = 1 and ab=32=9.a^b = 3^2 = 9. This gives 190=9,1 \cdot 9 - 0 = 9, which beats 23=82^3 = 8 and the other assignments.

Thus, the correct answer is D.

Problem 2 in Other Years