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 Question from ivan, a student: One person received the recommendation of a doctor taking the drug "Passaneura" every 10 hours. After a few days, noted that the time you should take the medication had not been repeated once. How many days since the first dose, will have to pass the time until recur

Hi Ivan,

The answer will depend on whether you are using a 12 hour clock or a 24 hour clock. I'm going to use a 12 hour clock.

The times on the clock repeat on a 12 hour cycle and the times at which the drug is taken repeat on a 10 hour cycle. You want a number that is a multiple of 12 and also a multiple of 10. In fact you want the smallest number which is a multiple of 12 and 10. This is commonly called the least common multiple (or LCM) of 12 and 10. If you don't know how to find the LCM then go to our Quandaries and Queries page and use the Quick Search to search for the term LCM.

Penny

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