SOLUTION: A pyramid of blocks has 26 blocks at the bottom row and 2 fewer blocks each successive row thereafter. How many blocks are there in the pyramid?

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Question 1188246: A pyramid of blocks has 26 blocks at the bottom row and 2 fewer blocks each
successive row thereafter. How many blocks are there in the pyramid?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
This is an arithmetic series with a1=2, and difference of 2 with 13 rows.
S=(n/2)(2a1+(n-1)d); (13/2) (52+12(-2))
=(13/2)(28)
=13(14)=182
26+24+22+20+18+16+14+12+10+8+6+4+2=182