2015 AMC 8 Problem 24

Attempt Problem 24 of the 2015 AMC 8 below, then check your answer against the video solution and professionally curated solution 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.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

24.

A baseball league consists of two four-team divisions. Each team plays every other team in its division NN games. Each team plays every team in the other division MM games with N>2MN > 2M and M>4.M > 4. Each team plays a 7676 game schedule.
How many games does a team play within its own division?
36 36
48 48
54 54
60 60
72 72
Answer: B
Concepts:Diophantine Equationmodular arithmetic
Small hint:
Write the schedule equation 3N+4M=76.3N+4M=76.
Big hint:
Use N>2M,N>2M, M>4,M>4, and the equation modulo 3.3.
Video solution:
Solution video thumbnail
Play video

Click to load, then click again to play

Written solution:
Each team plays 3N3N games within its own division and 4M4M games against the other division, so 3N+4M=76.3N+4M=76.
Since N>2M,N>2M, we have 3N>6M,3N>6M, and hence 76=3N+4M>10M.76=3N+4M>10M. Thus M<7.6.M<7.6. Together with M>4,M>4, this gives M∈{5,6,7}.M\in\{5,6,7\}.
Reducing 3N+4M=763N+4M=76 modulo 33 gives M≡1(mod3),M\equiv1\pmod3, so M=7.M=7. Therefore the team plays 4M=284M=28 non-division games and 76−28=4876-28=48 division games.
Thus, B is the correct answer.
LIVE by Po-Shen Loh
Programs

LIVE Classes

Self-Paced Classes

Stars

Scholarship

About Us

Who Is Po-Shen Loh?

Email Contact

Newsletter

Jobs

Become a Star

For a more Thought Full world.

© 2026 Expii, Inc.