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2022 AMC 12B Problem 1

Problem 1 of 25EasierAlgebra

Define xyx \diamond y to be xy|x - y| for all real numbers xx and y.y. What is the value of (1(23))((12)3)?(1 \diamond (2 \diamond 3)) - ((1 \diamond 2) \diamond 3)?

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Solution

Since 23=23=1,2 \diamond 3 = |2-3| = 1, we get 1(23)=11=0.1 \diamond (2 \diamond 3) = 1 \diamond 1 = 0. Since 12=12=1,1 \diamond 2 = |1-2| = 1, we get (12)3=13=13=2.(1 \diamond 2) \diamond 3 = 1 \diamond 3 = |1-3| = 2. The value is 02=2.0 - 2 = -2. Thus, the correct answer is A.

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Concepts: custom operation · absolute value · order of operations

Problem text and solution from the LIVE past-contest archive. See also the AoPS wiki page for community solutions.