Question

The G.C.D. of two whole numbers is $5$ and their L.C.M. is $60$. If one of the numbers is $20$, then the other number would be

• A. $23$
• B. $13$
• C. $16$
• D. $15$

Answer 1

The correct option is D $15$

If we are given two numbers $N_1$ and $N_2$ and their $G.C.D$ and $L.C.M.$.

then by property of numbers $N_1$$\times$$N_2=G.C.D$ $\times$ $L.C.M.$

Here Given:

$N_1=20$

$G.C.D.=5$

and $L.C.M=60$

Let, $N_2=x$

then from above relation

$20$$\times$$x=5$$\times$$60$

$=>x=\frac{300}{20}$

$=>x=15$