Question

Find the sum of all the numbers divisible by $6$ in between $100$ to $400$

• A. $12550$
• B. $12450$
• C. $11450$
• D. $11550$
• E. $11555$

Answer 1

The correct option is B $12450$

The sequence will be $102,108,114,120,.........,396$

Here $1$st term $a=102$(which is the $1$st term greater than $100$ that is divisible by $6$)

The last term less than $400$ which is divisible by $6$ is $396$

The number of terms in the A.P $102,108,114,...396$ is given by $\left[\frac{396-102}{6}\right]+1=50$ numbers

Common difference $=d=6$

So, $S=25(102+396)=12450$