2010 AMC 10B Problem 17

Below is the professionally curated solution for Problem 17 of the 2010 AMC 10B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2010 AMC 10B solutions, or check the answer key.

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Concepts:median (data)inequalitylogical deduction

Difficulty rating: 1600

17.

Every high school in the city of Euclid sent a team of 33 students to a math contest. Each participant in the contest received a different score. Andrea's score was the median among all students, and hers was the highest score on her team. Andrea's teammates Beth and Carla placed 37th37^\text{th} and 64th,64^\text{th}, respectively. How many schools are in the city?

2222

2323

2424

2525

2626

Solution:

Let there be xx schools. Then there are 3x3x participants in the contest.

Since everyone has a unique score, there is also a unique median. This means xx is odd.

Note there are at least 2323 teams, since otherwise a 64th64^\text{th} placed wouldn't exist.

We also have at most 2323 teams, since otherwise we have Andrea's place as being greater than Beth's.

This means that there are 2323 teams.

Thus, B is the correct answer.

Problem 17 in Other Years