2007 AMC 8 Problem 7

Attempt Problem 7 of the 2007 AMC 8 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 2007 AMC 8 solutions, or check the answer key.

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The average age of $5$ people in a room is $30$ years. An $18$ -year-old person leaves the room. What is the average age of the four remaining people?

$25$

$26$

$29$

$33$

$36$

Answer: D

Concepts:mean

Difficulty rating: 900

Solution:

Initially, the total age of everyone in the room is $5 \cdot 30 = 150$ years.

After the person leaves, the total age is $150 - 18 = 132.$ With $4$ people remaining, the average age becomes $\dfrac{132}{4} = 33.$

Thus, D is the correct answer.

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