Thread: Help with a bus problem
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Old December 4th, 2008, 05:20 PM
Soroban Soroban is offline
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Hello, fecoupefe!

Quote:
The 101 passes John's house every 8 minutes.
The 103 bus passes it every 12 minutes.
The two buses last passed by together at 9:00 am.
When is the next time that will happen?

The very worst you can do is make a list . . .

. . \begin{array}{cccccccccc} \text{101 bus:} & 9\!:\!00 & 9\!:\!08 & 9\!:\!16 & {\color{red}9\!:\!24} & 9\!:\!32 & 9\!:\!40 & 9\!:\!48 & \hdots\\ \text{103 bus:} & 9\!:\!00 & 9\!:\!12 & {\color{red}9\!:\!24} & 9\!:\!36 & 9\!:\!48 & \hdots\end{array}

They pass together at 9:24 am.



The easier way is to find the Least Common Multiple of 8 and 12: .\text{LCM}(8,12) \:=\:24

They will pass together every 24 minutes.


Too fast for me, nzmathman . . .
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