
Donald S. answered 01/08/15
Tutor
New to Wyzant
Interactive Chemical Educator for Chemistry
Let m be the number of main floor seats sold and b be the number of balcony seats sold.
870 = 11m + 7b
m = 2b
870 = 11(2b) + 7b = 22b + 7b = 29b
b = 30
m = 60
They sold 60 main floor seats and 30 balcony seats.