Question

Three number are in the ratio of $3:4:5$ and their L.C.M. is $2400$. Their H.C.F. is:

• A. $40$
• B. $80$
• C. $120$
• D. $200$

Answer 1

The correct option is A $40$

Let the numbers be $3x$, $4x$ and $5x$.
Then, their L.C.M. $=60x$.
So, $60x=2400$ or $x=40$.
$\therefore$ The numbers are $(3\times 40)$, $(4\times 40)$ and $(5\times 40)$.
Hence, required H.C.F. $=40$.