Question

In a theater, there are 14 seats in the first row, 18 seats in the second row, 22 seats in the third row, and so on. How many seats are in the 18th row

Answer 1

Answer:

There are 82 number of seats in the 18th row.

Step-by-step explanation:

Given that,  there are 14 seats in the first row, 18 seats in the second row, 22 seats in the third row, and so on.

i.e (14, 18, 22, ........so on)

This series is in Arithmetic Progression.

Here,

a = initial term = 14

d = common difference = 4

As we have to calculate number of seats in 18th row, so we have find n₁₈

We know that,

$a_n=a_1+(n-1)d$

Putting the values,

$a_{18}=14+(18-1)4$

$=14+(17)4$

$=14+68$

$=82$

Answer 2

Since you are adding by 4 each time you get to a new row just follow the pattern. 

In the 18th row there are: 82 seats.