The stadium tickets are priced at $10 and $8.  The number of $10-dollar tickets available is  2²₃ that of the number of $8-dollar tickets. 2 out of 5 of the $10-dollar tickets and all the $8-dollar tickets were sold. The ticket sales amounted to $840. How much more would have been collected if all the tickets were sold?

	$10	$8
Comparing $10 and $8 tickets at first	8x5 = 40 u	3x5 = 15 u
Before	5x8 = 40 u
Change	- 2x8 = - 16 u	- 15 u
After	3x8 = 24 u	0 u

The number of 10 tickets at first is repeated.  Make the number of 10 tickets the same.  LCM of 5 and 8 is 40.

2²₃ = ⁸₃

Number of $10 tickets : $8 tickets = 8 : 3

	$10	$8	Total
Number	16 u	15 u
Value	$10	$8
Total value	160 u	120 u	$840

Total amount collected from the sale of the sold tickets
= 160 u + 120 u
= 280 u

1 u = 840 ÷ 280 = 3

Number of $10-tickets left unsold
= 24 u 
= 24 x 3
= 72

More amount to be collected if all the tickets were sold
= 72 x 10
= $720

Answer(s): $720