The bird park tickets are priced at $11 and $5.  The number of $11-dollar tickets available is  1¹₆ that of the number of $5-dollar tickets. 2 out of 3 of the $11-dollar tickets and all the $5-dollar tickets were sold. The ticket sales amounted to $1220. How much more would have been collected if all the tickets were sold?

	$11	$5
Comparing $11 and $5 tickets at first	7x3 = 21 u	6x3 = 18 u
Before	3x7 = 21 u
Change	- 2x7 = - 14 u	- 18 u
After	1x7 = 7 u	0 u

The number of 11 tickets at first is repeated.  Make the number of 11 tickets the same.  LCM of 3 and 7 is 21.

1¹₆ = ⁷₆

Number of $11 tickets : $5 tickets = 7 : 6

	$11	$5	Total
Number	14 u	18 u
Value	$11	$5
Total value	154 u	90 u	$1220

Total amount collected from the sale of the sold tickets
= 154 u + 90 u
= 244 u

1 u = 1220 ÷ 244 = 5

Number of $11-tickets left unsold
= 7 u 
= 7 x 5
= 35

More amount to be collected if all the tickets were sold
= 35 x 11
= $385

Answer(s): $385