Question 1201456
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Use the formula for the sum of n first term of an arithmetic progression.


About this formula, look into the lessons

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/Arithmetic-progressions.lesson>Arithmetic progressions</A>

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=http://www.algebra.com/algebra/homework/Sequences-and-series/The-proofs-of-the-formulas-for-arithmetic-progressions.lesson>The proofs of the formulas for arithmetic progressions</A> 

in this site.


Your progression has first term 18, the common difference of 8
and the number of terms 103.



This exercise will only be useful for you, if you will perform it on your own.