The concert hall tickets are priced at $22 and $18.  The number of $22-dollar tickets available is  1¹₃ that of the number of $18-dollar tickets. 3 out of 7 of the $22-dollar tickets and all the $18-dollar tickets were sold. The ticket sales amounted to $5778. How much more would have been collected if all the tickets were sold?

	$22	$18
Comparing $22 and $18 tickets at first	4x7 = 28 u	3x7 = 21 u
Before	7x4 = 28 u
Change	- 3x4 = - 12 u	- 21 u
After	4x4 = 16 u	0 u

The number of 22 tickets at first is repeated.  Make the number of 22 tickets the same.  LCM of 7 and 4 is 28.

1¹₃ = ⁴₃

Number of $22 tickets : $18 tickets = 4 : 3

	$22	$18	Total
Number	12 u	21 u
Value	$22	$18
Total value	264 u	378 u	$5778

Total amount collected from the sale of the sold tickets
= 264 u + 378 u
= 642 u

1 u = 5778 ÷ 642 = 9

Number of $22-tickets left unsold
= 16 u 
= 16 x 9
= 144

More amount to be collected if all the tickets were sold
= 144 x 22
= $3168

Answer(s): $3168