The park tickets are priced at $21 and $11.  The number of $21-dollar tickets available is  1⁴₅ that of the number of $11-dollar tickets. 2 out of 5 of the $21-dollar tickets and all the $11-dollar tickets were sold. The ticket sales amounted to $7183. How much more would have been collected if all the tickets were sold?

	$21	$11
Comparing $21 and $11 tickets at first	9x5 = 45 u	5x5 = 25 u
Before	5x9 = 45 u
Change	- 2x9 = - 18 u	- 25 u
After	3x9 = 27 u	0 u

The number of 21 tickets at first is repeated.  Make the number of 21 tickets the same.  LCM of 5 and 9 is 45.

1⁴₅ = ⁹₅

Number of $21 tickets : $11 tickets = 9 : 5

	$21	$11	Total
Number	18 u	25 u
Value	$21	$11
Total value	378 u	275 u	$7183

Total amount collected from the sale of the sold tickets
= 378 u + 275 u
= 653 u

1 u = 7183 ÷ 653 = 11

Number of $21-tickets left unsold
= 27 u 
= 27 x 11
= 297

More amount to be collected if all the tickets were sold
= 297 x 21
= $6237

Answer(s): $6237