The bird park tickets are priced at $12 and $10.  The number of $12-dollar tickets available is  2²₅ that of the number of $10-dollar tickets. 3 out of 4 of the $12-dollar tickets and all the $10-dollar tickets were sold. The ticket sales amounted to $1580. How much more would have been collected if all the tickets were sold?

	$12	$10
Comparing $12 and $10 tickets at first	12x1 = 12 u	5x1 = 5 u
Before	4x3 = 12 u
Change	- 3x3 = - 9 u	- 5 u
After	1x3 = 3 u	0 u

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

2²₅ = ¹²₅

Number of $12 tickets : $10 tickets = 12 : 5

	$12	$10	Total
Number	9 u	5 u
Value	$12	$10
Total value	108 u	50 u	$1580

Total amount collected from the sale of the sold tickets
= 108 u + 50 u
= 158 u

1 u = 1580 ÷ 158 = 10

Number of $12-tickets left unsold
= 3 u 
= 3 x 10
= 30

More amount to be collected if all the tickets were sold
= 30 x 12
= $360

Answer(s): $360