2026 AMC 8 Problem 20

Attempt Problem 20 of the 2026 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 2026 AMC 8 solutions, or check the answer key.

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

20.

The land of Catania uses gold coins and silver coins. Gold coins are 11 mm thick and silver coins are 33 mm thick. In how many ways can Taylor make a stack of coins that is 88 mm tall using any arrangement of gold and silver coins, assuming order matters?
33
77
1010
1313
1616
Answer: D
Concepts:partitions and compositionscombinationscasework
Small hint:
Count by the number of silver coins
Big hint:
With kk silver coins, arrange kk S’s and 8−3k8-3k G’s
Video solution:
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Written solution:
Count by the number of silver coins. With no silver coins, there is 11 stack. With one silver coin, there are 55 gold coins and 11 silver coin, so 66 arrangements. With two silver coins, there are 22 gold coins and 22 silver coins, so (42)=6\binom42=6 arrangements. More silver coins are too thick. The total is 1+6+6=131+6+6=13.
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