The drama centre had 1728 seats. There were 40% fewer $35-seats than $5-seats. 60% of the $5-seats and some $35-seats were sold. A total of $19865 was collected. How many seats were unsold?

	$35	$5	Total
Number	3 u	5 u	8 u

100% - 40% = 60%
⁶⁰₁₀₀ = ³₅

Total number of seats
= 3 u + 5 u
= 8 u

8 u = 1728

1 u = 1728 ÷ 8 = 216

Total number of $5-seat tickets
= 5 u
= 5 x 216
= 1080

Number of $5-seat tickets sold
= 60% x 1080
= ⁶⁰₁₀₀ x 1080
= 648

Amount collected from $5-seat tickets sold
= 648 x 5
= $3240

Amount collected from $35-seat tickets sold
= 19865 - 3240
= $16625

Number of $35-seat tickets sold
= 16625 ÷ 35
= 475

Number of tickets sold
= 648 + 475
= 1123

Number of tickets left unsold
= 1728 - 1123
= 605

Answer(s): 605