1991 AMC 8 Problem 13
Attempt Problem 13 of the 1991 AMC 8 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 1991 AMC 8 solutions, or check the answer key.
All problems are used with official legal permission of the Mathematical Association of America (MAA).
13.
How many zeros are at the end of the product
Answer: C
Small hint:
A trailing zero comes from a factor of
Big hint:
Count the total factors of and of the number of trailing zeros is the smaller count
Solution:
Since the seven ’s give Since the three ’s give
The number of trailing zeros is
Thus, the correct answer is C .
Problem 13 in other years
- 1985 AMC 8
- 1986 AMC 8
- 1987 AMC 8
- 1988 AMC 8
- 1989 AMC 8
- 1990 AMC 8
- 1992 AMC 8
- 1993 AMC 8
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