Question

An amphitheatre has 18 seats in the first row, 20 in the second, 22 in the third, and so on, for 22 rows. How many seats are in the amphitheatre?
The amphitheatre has seats,

Answer 1

18+20+22+24+26+28+30+32+34+36+38+40+42+44+46+48+50+52+54+56+58+60 = 858 seats

Since it’s 18 first then 20 and 22 you have to add two to 22 19 more times and then add 18 and 20