Answers

2014-12-13T08:07:07+05:30
Factors of 20 = 1 , 2 , 4 , 5 , 10 , 20.

Factors of 30 = 1 , 2 , 3 , 5 , 10 , 15 , 30.

Common factors of 20 and 30 = 1, 2 , 5 , 10

So 

The greatest common factor 20 and 30 is 10.


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2014-12-13T09:56:16+05:30
Factorising 20 and 30 we have
     Factors of 20 = 1 , 2 , 4 , 5 , 10 , 20. 
     Factors of 30 = 1 , 2 , 3 , 5 , 10 , 15 , 30.
     Common factors of 20 and 30 = 1, 2 , 5 , 10

The greatest common factor 20 and 30 is 10.
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