Question

a pile of bricks has 85 bricks in the bottom row, 79 bricks in the second row, 73 in the third row, and so on until there is only 1 brick in the top row.

how many bricks are in the 12th row?

how many rows are there in all?
You have an arithmetic sequence where
a = 85 , d = -6

12th row = 85 + 11(-6) = 19

row(n ) = a + (n-1)d
1 = 85 + (n-1)(-6)
1 = 85 - 6n + 6
6n = 90
n = 15
there are 15 rows
Math
Can tou explain how you got the 6
Can you explain how the 6 came about

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