The park tickets are priced at $15 and $9.  The number of $15-dollar tickets available is  1¹₆ that of the number of $9-dollar tickets. 3 out of 5 of the $15-dollar tickets and all the $9-dollar tickets were sold. The ticket sales amounted to $5850. How much more would have been collected if all the tickets were sold?

	$15	$9
Comparing $15 and $9 tickets at first	7x5 = 35 u	6x5 = 30 u
Before	5x7 = 35 u
Change	- 3x7 = - 21 u	- 30 u
After	2x7 = 14 u	0 u

The number of 15 tickets at first is repeated.  Make the number of 15 tickets the same.  LCM of 5 and 7 is 35.

1¹₆ = ⁷₆

Number of $15 tickets : $9 tickets = 7 : 6

	$15	$9	Total
Number	21 u	30 u
Value	$15	$9
Total value	315 u	270 u	$5850

Total amount collected from the sale of the sold tickets
= 315 u + 270 u
= 585 u

1 u = 5850 ÷ 585 = 10

Number of $15-tickets left unsold
= 14 u 
= 14 x 10
= 140

More amount to be collected if all the tickets were sold
= 140 x 15
= $2100

Answer(s): $2100