What is the least common multiple of 9 and 15?

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Answer 1 · 2018-02-26T18:51:17

#45#

First we need to write out the prime factors of #9# and #15#.

#9:3xx3#
#15:3xx5#

Now we group them together:
#9:(3xx3)#
#15:(3)xx(5)#

Next we take the largest groups of each number:
#9# has two #3#s while #15# has 1 #5#.

We multiply the largest groups together:
#LCM(9,15)=3xx3xx5=45#

#45/15=3#, #45/9=5#

Answer 2 · 2018-02-28T08:53:27

#lcm(9,15)=45#

listing the multiples

multiples of #9:" "{9,18,27,36,color(red)(45),54,63,72,81,color(red)(90),99,...}#

multiples of #15:" "{15,30,color(red)(45),60,75,color(red)(90),105,..}#

common multiples#" "{45,90,...}#

#lcm(9,15)=45#