A Math 148 student set three clocks with different snooze alarms. Clock A goes off every 15 minutes, clock B every 40 minutes, and clock C every 45 minutes. If all three clocks go off at 6:00 am, how long will it be for all three clocks to go off simultaneously after that time?

Question

anonymous · Answer

Find the LCM of 15, 40 and 45
Then calculate the time....

anonymous · Answer

wouldn't that by 5?

anonymous · Answer

be*

anonymous · Answer

no that is their HCF..
You have to find the Lowest Common MULTIPLE.......

anonymous · Answer

so multiply each number until you get the same number for all three?

anonymous · Answer

that is the longer method.
Don't you know the ladder division method??

anonymous · Answer

nope

anonymous · Answer

which standard/class r u in??

anonymous · Answer

I'm in college. But thats common core so I've never had to use it

anonymous · Answer

ok, then write tables of each number till you find the first common multiple

retireed · Answer

Don't feel lonely, I have a masters in engineering and I never heard of the ladder division method.  Time for google.

anonymous · Answer

15, 30, 45, 60, 75, 90, ---------
40, 80, 120, 160, ---------
45, 90, 135, 180, ---------

anonymous · Answer

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further steps in nest pic..