The stadium tickets are priced at $11 and $5.  The number of $11-dollar tickets available is  1¹₃ that of the number of $5-dollar tickets. 2 out of 5 of the $11-dollar tickets and all the $5-dollar tickets were sold. The ticket sales amounted to $815. How much more would have been collected if all the tickets were sold?

	$11	$5
Comparing $11 and $5 tickets at first	4x5 = 20 u	3x5 = 15 u
Before	5x4 = 20 u
Change	- 2x4 = - 8 u	- 15 u
After	3x4 = 12 u	0 u

The number of 11 tickets at first is repeated.  Make the number of 11 tickets the same.  LCM of 5 and 4 is 20.

1¹₃ = ⁴₃

Number of $11 tickets : $5 tickets = 4 : 3

	$11	$5	Total
Number	8 u	15 u
Value	$11	$5
Total value	88 u	75 u	$815

Total amount collected from the sale of the sold tickets
= 88 u + 75 u
= 163 u

1 u = 815 ÷ 163 = 5

Number of $11-tickets left unsold
= 12 u 
= 12 x 5
= 60

More amount to be collected if all the tickets were sold
= 60 x 11
= $660

Answer(s): $660