Question

Every 3 days William has to take medication for his back. Every 7 days he has to take medication for his asthma. On what day William take take both medications?

(LCM)

Answer 1

On the 21st day; the 7th day of the back medication and the 3rd day of the asthma medication.

Answer 2

Answer: William will take both medications on every 21 days.

Explanation:

Given: Every 3 days William has to take medication for his back. Every 7 days he has to take medication for his asthma.

To find the on what day William take take both medications, we need to find the LCM ( least common multiple) of 3 and 7.

Since 3 and 7 are both coprime numbers therefore, the LCMof 3 and 7 is given by:-

`L.C.M.(3,7)=3*7=21`

Hence, William will take both medications on every 21 days.