Question

A large multiplex movie house has many theaters. The largest theater has 50 rows. There are 12 seats in the first row. Each row has two seats more than the previous row. How many total seats are there in this theater?

Answer 1

a(50) = a(1)+ (50-1)d = 20 + 34*2 = 20+78 = 98

Ans: S(50) = (n/2)(a(1)+a(50)) = (50/2)(20+98) = 50*59 = 1365

Explanation: