Question

What is the greatest common factor of $45,135$ and $270$?

• A. $5$
• B. $9$
• C. $15$
• D. $25$
• E. $45$

Answer 1

The correct option is E $45$

The factors of the given numbers are:

$45=1,3,5,9,15$ and $45$
$135=1,3,5,9,15,45$ and $135$
$270=1,3,5,9,15,45,90,135$ and $270$

The common factors in each of the above numbers are $3,3$ and $5$.

Hence, the greatest common factor is $3\times 3\times 5=45$

and as $45$ is also a factor of both $135$ and $270$

Hence the GCF of $45,135$ and $270$ is $45$