Difference between revisions of "2001 AMC 10 Problems/Problem 8"
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== Problem == | == Problem == | ||
| − | + | A church rings its bells every 15 minutes, the school rings its bells every 20 minutes and the day care center rings its bells every 25 minutes. If they all ring their bells at noon on the same day, at what time will they next all ring their bells together? (Answer in the form AB:CD without am or pm, such as 08:00) | |
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== Solution == | == Solution == | ||
Revision as of 11:31, 11 November 2022
Problem
A church rings its bells every 15 minutes, the school rings its bells every 20 minutes and the day care center rings its bells every 25 minutes. If they all ring their bells at noon on the same day, at what time will they next all ring their bells together? (Answer in the form AB:CD without am or pm, such as 08:00)
Solution
We need to find the least common multiple of the four numbers given. That is, the next time they will be together.
First, find the least common multiple of 
and 
.
.
Find the least common multiple of 
and 
.
Since is a multiple of , the least common multiple is .
Lastly, the least common multiple of and 
is 
.
See Also
| 2001 AMC 10 (Problems • Answer Key • Resources) | ||
| Preceded by Problem 7 |
Followed by Problem 9 | |
| 1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 • 9 • 10 • 11 • 12 • 13 • 14 • 15 • 16 • 17 • 18 • 19 • 20 • 21 • 22 • 23 • 24 • 25 | ||
| All AMC 10 Problems and Solutions | ||
The problems on this page are copyrighted by the Mathematical Association of America's American Mathematics Competitions. 
