Question

Find the ratio between LCM and HCF of 5, 15 and 20.

Answer 1

LCM (5, 15, 20) = $2|\underset{–}{5,15,20}2|\underset{–}{5,15,10}3|\underset{–}{5,15,5}5|\underset{–}{5,5,5}|1,1,1$

LCM = $2\times 2\times 3\times 5=60$

$5=1\times 5$

$15=3\times 5$

$20=2\times 2\times 5$

So, HCF (5, 15, 20)=5

$\frac{LCM}{HCF}=\frac{60}{5}=12$