Question

A meeting hall has 20 seats in the first row 24 seat inthe second row 28 seat in the third row and so o and has in all 30 rows how any seats are there in the meeting hall

Answer 1

First row has 20 seats..

Second row has 24 seats..

Third row has 28 seats..

There are total of 30 rows.

So, let a = 20

d = (24-20) = 4

n = 30

Therefore, total seats are given by, n/2{2a+(n-1)d}

15{40+(30-1)4}

15{40+(29)4}

15(40+116)

15(156)

==】So, total number of seats in the hall are 2,340.

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Hope it helps.