2015 AMC 8 Problem 5

Below is the video solution and professionally curated solution for Problem 5 of the 2015 AMC 8, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2015 AMC 8 solutions, or check the answer key.

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Concepts:range

Difficulty rating: 770

5.

Billy's basketball team scored the following points over the course of the first 1111 games of the season:

42,47,53,53,58,58,58,61,64,65,73.42, 47, 53, 53, 58, 58, 58, 61, 64, 65, 73.

If his team scores 4040 in the 12th12^{\text{th}} game, which of the following statistics will show an increase?

range \text{range}

median \text{median}

mean \text{mean}

mode \text{mode}

midrange

Video solution:
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Written solution:

When considering all 1212 games, 4040 -- from the 12th12^{\text{th}} game -- will be the lowest score. Therefore, compared to the range of just the first 1111 games, the range of all 1212 games would increase from 7342=3173-42 = 31 to 7340=33.73-40=33.

Thus, the correct answer is A .

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