Question

The sum of first three common multiples of $4,5$ and $6$ is

• A. $20$
• B. $80$
• C. $360$
• D. $120$

Answer 1

The correct option is C

$360$

Step 1: Multiples and Common multiples

1. A multiple of a number is a number that is the product of a given number and other natural number.
2. Multiples that are common to two numbers are known as common multiples of those numbers.

Step 2: Explanation for correct answer

Option (c): $360$

Find the common multiples of $4,5,6$

LCM of $4,5$ and $6=60$

Common multiples are $60,120,180$.

Sum of common multiples $=60+120+180$

Sum of common multiples $=360$

Thus, option (c) is the correct answer.

Step 3: Explanation for incorrect answers

Option (a): $20$

Option (b): $80$

Option (d): $120$

By determining the sum of first three common multiples of $4,5$ and $6$ is $360$.

Thus, option (a), (b) and (d) are incorrect answers.

Hence, option (c) is the correct answer.