SOLUTION: How many common multiples of 14 and 21 are there between 200 and 400?

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Question 1049660: How many common multiples of 14 and 21 are there between 200 and 400?
Found 3 solutions by ikleyn, MathTherapy, Alan3354:
Answer by ikleyn(52787) About Me  (Show Source):
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How many common multiples of 14 and 21 are there between 200 and 400?
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Common multiples of 14 and 21 are those and only those integer numbers that are multiple of LCM(14,21) = 42.


There are not so many multiples of 42 between 200 and 400. 
They are 210, 252, 294, 336 and 378.


Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

How many common multiples of 14 and 21 are there between 200 and 400?
LCM of 14 and 21 is 42

There are 5 multiples of 42, between 200 and 400. They are: highlight_green%28matrix%285%2C+1%2C+210%2C+252%2C+294%2C+336%2C+378%29%29

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The LCM is 42.
--> 42 times 5, 6, 7, 8 & 9.