Patrick B. answered 04/01/19
Math and computer tutor/teacher
4s + 5e = 80 is the main equation that relates the number of tickets sold of each type.
SOlving for s:
4s = 80 - 5e
s = (80 - 5e)/4
Solving for e:
e = (80 - 4s)/5
You can now find the of tickets of each type given the other type.
For example, if 4 non-student tickets were sold, then e=4 in the first formula:
s = (80 - 5*4)/4 = (80 -20)/4 = 60/4 = 15 student tickets were sold.
On the other hand, for example, if 10 student tickets were sold, then
s=10 and e = (80 -4*10)/5 = (80 - 40)/5 = 40/5 = 8 non-student tickets were sold.