Question

An auditorium has 20 seats in the 1st row, 24 seats on the second row, 28 seats on the third row, and so on up to the 20th row.. How many seats are there in the last row? How many seats are there in the auditorium?​

Answer 1

Answer: 100 seats at 20th row

Explanation:

1st row & 2nd-row seats difference= 24-20 =4

2nd-row & 3rd row seats difference= 28-24 =4

Every row has extra 4 seats than the row before.

20th row there will be extra seats than the 1st row= (20*4)= 80 seats

So, 20th row seat= 20+80 = 100 seats