Question

There are 25 rows of seats in an auditorium. The first row is of 20 Sears the second seats of 22 rows the third of 24 seats and so on How many chairs are there in 21st row

Answer 1

here is ur ans
----------------------

a=20
d=22-20 =2
an = a+(n-1)d
an =20+ (20) *2
an = 60
--------------------------
hope it helps
mark BRAINLIEST

Answer 2

Answer: 60

Step-by-step explanation:

Answer: 60.

Step-by-step explanation:

The number of seats will be in the following order-

20, 22, 24,.........

It clearly forms an arithmetic sequence.

From the question, you have

a= 20 (first term), d= 2 (common diff)

n=21 (asked) , t21=?

The formula of general term is

tn = a+(n-1)d

t21 = 20+(21-1)2

= 20+ (20)2

= 20+40

= 60.

Hope I helped you!