Question

Using Prime Factorisation Method, determine the HCF of the numbers : $10,15,30$

Answer 1

First of all lets find the prime factors of both $10,15,30$

$2$	$10$	$3$	$15$
$5$	$5$	$5$	$5$
	$1$		$1$
Prime factors of $10$ are $2\times 5$		Prime factors of $15$ are $3\times 5$

$2$	$30$
$3$	$15$
$5$	$5$
	$1$
Prime factors of $30$ are $2\times 3\times 5$

Now to find the HCF we need to find the common factors of all the numbers

which are $5$ (which occurs only one time in all the three factors)

so $HCF$ of $10,15,30$ is $5$