A theather can seat 621 people. The number of rows is 4 less than the number of seats in each row. How many rows of seats are there?

Answer 1

R = S-4

SR =621 = (S-4)S= S^2 -4S

S^2 -4S = 621

S^2 -4S + 4 = 621+4 = 625

(S-2)^2 = sqr625

S-2 = sqr625 = 25+2 = 27 seats per row

and R =27-4 = 23 rows

23 x 27 = 621 seats total, with 27 seats per row for 23 rows