2007 AMC 10B Problem 2 — Solution | LIVE by Po-Shen Loh

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2007 AMC 10B Problem 2

Below is the professionally curated solution for Problem 2 of the 2007 AMC 10B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2007 AMC 10B solutions, or check the answer key.

All of the real AMC 8, AMC 10, AMC 12, and AIME problems in our complete solution collection are used with official legal permission of the Mathematical Association of America (MAA).

Concepts:custom operation order of operations

Difficulty rating: 870

2.

Define the operation $\star$ by $a\star b = (a+b)b.$ What is $(3\star 5)-(5\star 3)?$

$-16$

$-8$

$0$

$8$

$16$

Solution:

Since $3\star 5=(3+5)\cdot 5=40$ and $5\star 3=(5+3)\cdot 3=24,$ the difference is $40-24=16.$

Thus, the correct answer is E.

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Problem 2 in Other Years

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