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?
how many bricks are in the 12th row?
how many rows are there in all?
Answers
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
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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