The zoo tickets are priced at $18 and $12.  The number of $18-dollar tickets available is  2³₅ that of the number of $12-dollar tickets. 3 out of 7 of the $18-dollar tickets and all the $12-dollar tickets were sold. The ticket sales amounted to $4488. How much more would have been collected if all the tickets were sold?

	$18	$12
Comparing $18 and $12 tickets at first	13x7 = 91 u	5x7 = 35 u
Before	7x13 = 91 u
Change	- 3x13 = - 39 u	- 35 u
After	4x13 = 52 u	0 u

The number of 18 tickets at first is repeated.  Make the number of 18 tickets the same.  LCM of 7 and 13 is 91.

2³₅ = ¹³₅

Number of $18 tickets : $12 tickets = 13 : 5

	$18	$12	Total
Number	39 u	35 u
Value	$18	$12
Total value	702 u	420 u	$4488

Total amount collected from the sale of the sold tickets
= 702 u + 420 u
= 1122 u

1 u = 4488 ÷ 1122 = 4

Number of $18-tickets left unsold
= 52 u 
= 52 x 4
= 208

More amount to be collected if all the tickets were sold
= 208 x 18
= $3744

Answer(s): $3744