Answer
$S_{17}=918$
Work Step by Step
The first n term of an arithmetic sequence can be calculated as:
$S_n=\frac{n}{2}(a_1+a_n)$
We have to find the sum of the multiples of 6 from 6 to 102.
$a_1=6$
$a_{n}=102$
There are $102\div 6=17$ multiples of 6 from 6 to 102, inclusive.
Therefore we can substitute in the formula of the sum, and we get:
$S_{17}=\frac{17}{2}(6+102))=8.5\times108=918$
