The museum tickets are priced at $25 and $15.  The number of $25-dollar tickets available is  1¹₃ that of the number of $15-dollar tickets. 2 out of 3 of the $25-dollar tickets and all the $15-dollar tickets were sold. The ticket sales amounted to $3685. How much more would have been collected if all the tickets were sold?

	$25	$15
Comparing $25 and $15 tickets at first	4x3 = 12 u	3x3 = 9 u
Before	3x4 = 12 u
Change	- 2x4 = - 8 u	- 9 u
After	1x4 = 4 u	0 u

The number of 25 tickets at first is repeated.  Make the number of 25 tickets the same.  LCM of 3 and 4 is 12.

1¹₃ = ⁴₃

Number of $25 tickets : $15 tickets = 4 : 3

	$25	$15	Total
Number	8 u	9 u
Value	$25	$15
Total value	200 u	135 u	$3685

Total amount collected from the sale of the sold tickets
= 200 u + 135 u
= 335 u

1 u = 3685 ÷ 335 = 11

Number of $25-tickets left unsold
= 4 u 
= 4 x 11
= 44

More amount to be collected if all the tickets were sold
= 44 x 25
= $1100

Answer(s): $1100