The park tickets are priced at $15 and $10.  The number of $15-dollar tickets available is  1¹₂ that of the number of $10-dollar tickets. 3 out of 5 of the $15-dollar tickets and all the $10-dollar tickets were sold. The ticket sales amounted to $1880. How much more would have been collected if all the tickets were sold?

	$15	$10
Comparing $15 and $10 tickets at first	3x5 = 15 u	2x5 = 10 u
Before	5x3 = 15 u
Change	- 3x3 = - 9 u	- 10 u
After	2x3 = 6 u	0 u

The number of 15 tickets at first is repeated.  Make the number of 15 tickets the same.  LCM of 5 and 3 is 15.

1¹₂ = ³₂

Number of $15 tickets : $10 tickets = 3 : 2

	$15	$10	Total
Number	9 u	10 u
Value	$15	$10
Total value	135 u	100 u	$1880

Total amount collected from the sale of the sold tickets
= 135 u + 100 u
= 235 u

1 u = 1880 ÷ 235 = 8

Number of $15-tickets left unsold
= 6 u 
= 6 x 8
= 48

More amount to be collected if all the tickets were sold
= 48 x 15
= $720

Answer(s): $720