Answer:
Number of box seats = 1000
Number of lower deck seats = 5000
Number of upper deck seats = 4000
Step-by-step explanation:
Let number of box seats = 
Let number of lower deck seats = 
Let number of upper deck seats = 
As per question statement:
 ...... (1)
 ...... (1)
Cost for box seat = $10
Cost for  box seats = 10
 box seats = 10
Cost for lower deck seat = $8
Cost for  lower deck seats = 8
 lower deck seats = 8
Cost for lower deck seat = $5
Cost for  lower deck seats = 5
 lower deck seats = 5
As per question statement:
 ..... (2)
 ..... (2)
 ..... (3)
 ..... (3)
Putting value of  in (1) and (2):
 in (1) and (2):
 ....... (4)
 ....... (4)

 8  (4) - (5):
 (4) - (5):
 10000
10000

By (3):

Now, by equation (1):
 = 5000
 = 5000
Number of box seats = 1000
Number of lower deck seats = 5000
Number of upper deck seats = 4000