Question

a meeting hall has 20 seats in the first row ,24 seats in the second raw 28 states in the third row ,and so on and has in all 30 rows. row many seats are there in the meeting hall

Answer 1

Answer:

Step-by-step explanation

a=20, d=4

Sn =n/2{2a + (n-1) (d)}

S30= 30/2 (2×20+30-1×4)

=15 (40+116)

=15 × 156

=2340

Therefore 2340 seats are there in the meeting hall