The safari park tickets are priced at $20 and $16.  The number of $20-dollar tickets available is  2⁴₅ that of the number of $16-dollar tickets. 3 out of 5 of the $20-dollar tickets and all the $16-dollar tickets were sold. The ticket sales amounted to $8680. How much more would have been collected if all the tickets were sold?

	$20	$16
Comparing $20 and $16 tickets at first	14x5 = 70 u	5x5 = 25 u
Before	5x14 = 70 u
Change	- 3x14 = - 42 u	- 25 u
After	2x14 = 28 u	0 u

The number of 20 tickets at first is repeated.  Make the number of 20 tickets the same.  LCM of 5 and 14 is 70.

2⁴₅ = ¹⁴₅

Number of $20 tickets : $16 tickets = 14 : 5

	$20	$16	Total
Number	42 u	25 u
Value	$20	$16
Total value	840 u	400 u	$8680

Total amount collected from the sale of the sold tickets
= 840 u + 400 u
= 1240 u

1 u = 8680 ÷ 1240 = 7

Number of $20-tickets left unsold
= 28 u 
= 28 x 7
= 196

More amount to be collected if all the tickets were sold
= 196 x 20
= $3920

Answer(s): $3920