Question

A theater has 36 seats in the first row, 39 seats in the second row, 42 seats in the third row, and so on. How many seats are in the 18th row?
There are
seats in row 18

Answer 1

Answer: you'll have 87 seats in the 18th row

Step-by-step explanation:

an = a1+(n-1)d

a18= 36+(18-1)3

a18= 36+51

a18= 87

Answer 2

The 18th row will have 87 seats.

What is arithmetic progression?

'An arithmetic progression or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant.'

According to the given problem,

Number of seats in row 1 = 36

Number of seats in row 2 = 39

Number of seats in 3rd row = 42

Difference between the numbers ( d ) = 39 -36

                                                               = 3

We know, according to the formula of Arithmetic Progression,

$a_{n} = a_{1} + (n-1)d$

We need to find for the 18th row,

$a_{1}$ = 36

d = 3

n = 18

⇒ $a_{18}$ =  36 + ( 18 - 1 )×3

⇒ $a_{18}$ = 36 + 51

⇒  $a_{18}$ = 87

Hence, we can conclude, there will be 87 seats in the 18th row.

Learn more about arithmetic progression here: https://brainly.com/question/13989292

#SPJ2