Question

AN artist is arranging tiles in rows to decorate a wall each new row has 2 fewer tiles than the row below it if the first row has 23tiles how many tiles will be in the seventh row

Answer 1

Answer:

11

Step-by-step explanation:  

We have been given that tiles in each new row is 2 less than the row below it and the first roe has 23 tiles.

We can see that tiles in rows represents a arithmetic sequence. So we will use arithmetic sequence formula to find the number of tiles in 7th row.

$a_n=a_1+(n-1)d$, where $a_n$ is nth term of sequence, $a_1$ is first term of sequence and d is the common difference between consecutive terms.

Let us substitute our given values in above mentioned formula to find the 7th term of our arithmetic sequence.

$a_7=23+(7-1)(-2)$      

$a_7=23+(6)(-2)$        

$a_7=23-12$

$a_7=11$

Therefore, there will be 11 tiles in 7th row.