The stadium tickets are priced at $18 and $15.  The number of $18-dollar tickets available is  1³₄ that of the number of $15-dollar tickets. 3 out of 4 of the $18-dollar tickets and all the $15-dollar tickets were sold. The ticket sales amounted to $6180. How much more would have been collected if all the tickets were sold?

	$18	$15
Comparing $18 and $15 tickets at first	7x4 = 28 u	4x4 = 16 u
Before	4x7 = 28 u
Change	- 3x7 = - 21 u	- 16 u
After	1x7 = 7 u	0 u

The number of 18 tickets at first is repeated.  Make the number of 18 tickets the same.  LCM of 4 and 7 is 28.

1³₄ = ⁷₄

Number of $18 tickets : $15 tickets = 7 : 4

	$18	$15	Total
Number	21 u	16 u
Value	$18	$15
Total value	378 u	240 u	$6180

Total amount collected from the sale of the sold tickets
= 378 u + 240 u
= 618 u

1 u = 6180 ÷ 618 = 10

Number of $18-tickets left unsold
= 7 u 
= 7 x 10
= 70

More amount to be collected if all the tickets were sold
= 70 x 18
= $1260

Answer(s): $1260