novi
amit2k9
please post the complete question to have a better understanding.
Hello,
I simply tried to keep it short, but looks like i failed

It is the introductoin to the "Greatest Common Factor" out of the ManhattenGMAT Prep book. I hope I can write it down without violating any copyright.

"It is likely that you already know how to find both the GCF and the LCM. For example, when you reduce the fraction 9/12 to 3/4, you are dividing both the numerator (9) and the denominator (12) by 3, which is the GCF of 9 and 12.
When you add together the fractions 1/2 + 1/3 + 1/5, you convert the fractions to thiertieths: And so on and so on."
I know what the GCF is and I calculate with it alot. I still dont know the the factor of 1/5 here. Sometimes I cant see it.
Thank you.
I believe you won't violate any copyright if you post few questions from a book. So far you don't paste their entire content, it's just fine. In fact, the prep companies may see this as a free marketing of their book. A quality question may influence a reader to buy their entire book/study material. Moreover, most of the questions posted in this forum are from various prep sources and we don't hear any voice of objection from them.
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I still don't understand your question.
What do you mean by "factor of 1/5"?
You presented an example wherein you simplified a fraction by diving it with the GCD of numerator and denominator.
For, 1/2+1/3+1/5
Take LCM of (2,3,5), which is 30.
And proceed.
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