Question

solve it step by step​

Answer 1

-1 .,...............,........,........,...........

Answer 2

Answer: 2340

Step-by-step explanation:A.P: 20, 24, 28

a=20

d=24-20=4

And 28-24=4

n=30

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

=30/2(2*20+(30-1)(4)

=15*(40+116)

=15*156

=2340

So, total no. of chairs are 2340