Question

Inez waters her plants every two days.She trims them every 15 days.She did both today.When will she do both again?

please help me with this problem

Answer 1

You would look for the LCM of both the numbers and that would be the # of days until she will do both on the same day. in this case it would be 30.

Or if you want an easier way, here it is. if both or one of the numbers are prime sometimes multiplying them together will get you the answer as well.

It works in this case: 15 x 2 = 30

30 is your answer

hope this helps!

Answer 2

First find the multiples of 2 and 15,
multiples of 2 = 4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34................and so on
multiples of 15 = 15, 30, 45, 60 ..........and so on
Now, find the least common multiple between those two,
In this case, the least common multiple is 30,
So, she will do both again after 30 days.