Question

Hi guys !

Que : A meeting hall has 20 seats in first row , 24 seats in second row , 28 seats in third row and so on. There are 30 rows . How many seats are there in a meeting hall .

Anyone can answer this simple one ....

Thanks and mark as brainlist , to the answering guy ....​

Answer 1

Answer: 136

Step-by-step explanation:

It will be an A.P. Total rows (terms) =30

20, 24 ,28...…...........

a30 =a+29d

= 20+29×4

= 20+116

=136

Now sum

S36= n/2[a+a30]

= 30/2(20+136)

= 15×156

=2340