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?

Can tou explain how you got the 6

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 you explain how the 6 came about

To find the number of bricks in each row, we can observe that the number of bricks in each row forms a sequence. The first row has 85 bricks, and each subsequent row has 6 fewer bricks than the row below it.

To find the number of bricks in the 12th row, we can use the formula for the nth term of an arithmetic sequence:

nth term = first term + (n - 1) * common difference

In this case, the first term is 85, the common difference is -6, and we want to find the 12th term.

12th term = 85 + (12 - 1) * (-6)
= 85 + 11 * (-6)
= 85 - 66
= 19

So, there are 19 bricks in the 12th row.

To find the number of rows in total, we need to find the number of terms in the sequence. We can use the formula for the nth term:

nth term = first term + (n - 1) * common difference

In this case, the first term is 85, the common difference is -6, and we know that the nth term is 1. So we can set up the equation:

1 = 85 + (n - 1) * (-6)

Simplifying this equation:

1 = 85 - 6n + 6

6n = 90

n = 15

So, there are 15 rows in total.