1989 AMC 12 Problem 5
Attempt Problem 5 of the 1989 AMC 12 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 1989 AMC 12 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
5.
Toothpicks of equal length are used to build a rectangular grid as shown. If the grid is toothpicks high and toothpicks wide, then the number of toothpicks used is
Answer: E
Small hint:
Count horizontal and vertical toothpicks separately
Big hint:
A grid toothpicks wide has vertical grid lines
Solution:
There are vertical grid lines with toothpicks each, and horizontal grid lines with toothpicks each. The total is
Thus the correct answer is E.
Problem 5 in other years
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