Question

How to find the $LCM$ of $15,20$?

Answer 1

Find the $LCM$ of given numbers

The Least Common Multiple can be calculated in two ways; with the $LCM$ formula calculation of Highest Common Factor $\left(HCF\right)$, or multiplying the prime factors with the highest exponent factor.

Prime factors of $15$ are,

$15=3\times 5$

Prime factors of $20$ are,

$20=2\times 2\times 5$

$$\begin{gathered} HCF(15,20)=5 \\ LCM(15,20)=\frac{15\times 20}{5} \\ =\frac{300}{5} \\ =60 \end{gathered}$$

Hence, the $LCM$ of $15,20$ is $60$.