This is an arithmetic sequence of 15 terms with
a = 3, d = 2
sum(15) = (15/2)[ (2(3) + 14(2)) ]
= .....
A pike of blocks has 3 in the first row, 5 in the second row, 7 in the row and so on. If there are 15 rows how many blocks are there in all?
1 answer