Question

the first four common multiple of numbers $6,8,10$ are

• A. $10,20,30,40$
• B. $120,240,360,480$
• C. $8,40,80,120$
• D. $6,60,120,240$

Answer 1

The correct option is B $120,240,360,480$

$6=2\times 3$

$8=2^3$

$10=2\times 5$

$\Rightarrow$ LCM of $6,8,10=2^3\times 3\times 5=120$

$\therefore 120$ is the least common multiple of $6,8,10$. Thus, all multiples of $120$ are common multiples of $6,8$ and $10$.

$\therefore$ First four common multiples $=120,240,360,480$