The drama centre had 1764 seats. There were 20% fewer $40-seats than $5-seats. 60% of the $5-seats and some $40-seats were sold. A total of $20380 was collected. How many seats were unsold?

	$40	$5	Total
Number	4 u	5 u	9 u

100% - 20% = 80%
⁸⁰₁₀₀ = ⁴₅

Total number of seats
= 4 u + 5 u
= 9 u

9 u = 1764

1 u = 1764 ÷ 9 = 196

Total number of $5-seat tickets
= 5 u
= 5 x 196
= 980

Number of $5-seat tickets sold
= 60% x 980
= ⁶⁰₁₀₀ x 980
= 588

Amount collected from $5-seat tickets sold
= 588 x 5
= $2940

Amount collected from $40-seat tickets sold
= 20380 - 2940
= $17440

Number of $40-seat tickets sold
= 17440 ÷ 40
= 436

Number of tickets sold
= 588 + 436
= 1024

Number of tickets left unsold
= 1764 - 1024
= 740

Answer(s): 740