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# LCM question help please :) watch

1. I think this is a LCM question, but I'm not sure. Please could you give me the answer with an explanation. Thanks so much for your time!
Question:
Eddie owns three motorcycles. He cleans the Harley once every 8 days, the Honda once every 10 days and the Kawasaki every 15 days. Today he cleaned all three motorcycles. When will he next clean all three motorcycles on the same day?
2. (Original post by kellypeyton)
I think this is a LCM question, but I'm not sure. Please could you give me the answer with an explanation. Thanks so much for your time!
Question:
Eddie owns three motorcycles. He cleans the Harley once every 8 days, the Honda once every 10 days and the Kawasaki every 15 days. Today he cleaned all three motorcycles. When will he next clean all three motorcycles on the same day?
I'd rather stop short of giving you a full solution, that said:
You'll want to start by expressing 8, 10 and 15 in terms of prime factors, then proceed to find the LCM from there.
3. (Original post by kellypeyton)
I think this is a LCM question, but I'm not sure. Please could you give me the answer with an explanation. Thanks so much for your time!
Question:
Eddie owns three motorcycles. He cleans the Harley once every 8 days, the Honda once every 10 days and the Kawasaki every 15 days. Today he cleaned all three motorcycles. When will he next clean all three motorcycles on the same day?
Correct.

So how do you find the LCM?
4. hey, I think you can use the LCM venn diagram here but when i did these questions i always did them this way:

he cleans the harley every 8 days so:
8, 16 , 24 then keep +8 etc

he cleans the honda every 10 days so:
10, 20, 30 then keep + 10 etc

he cleans the kawaaki every 15 days so:
15, 30, 45 then keep +15 etc

keep doing the sequences until the same number appears in all 3 sequences that number will be the answer
5. The lowest common multiple is the first number that will appear as a common multiple when listing the multiples of each of those numbers.

Work it out and then you should apply it to the question - what does the LCM mean in this question ?

Clue: The difference between the number of days where the three motorcycles are cleaned on the same day.
6. Thank you all for your help! Okay so I know that the lcm is 120, would the answer simply be 'in 120 day's?
7. (Original post by kellypeyton)
Thank you all for your help! Okay so I know that the lcm is 120, would the answer simply be 'in 120 day's?
Yeah or after 120 days since they haven't specified what the date is today, so we cannot really calculate the date after 120 days.

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Updated: October 31, 2015
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