The theatre had 2673 seats. There were 20% fewer $25-seats than $20-seats. 80% of the $20-seats and some $25-seats were sold. A total of $34935 was collected. How many seats were unsold?

	$25	$20	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 = 2673

1 u = 2673 ÷ 9 = 297

Total number of $20-seat tickets
= 5 u
= 5 x 297
= 1485

Number of $20-seat tickets sold
= 80% x 1485
= ⁸⁰₁₀₀ x 1485
= 1188

Amount collected from $20-seat tickets sold
= 1188 x 20
= $23760

Amount collected from $25-seat tickets sold
= 34935 - 23760
= $11175

Number of $25-seat tickets sold
= 11175 ÷ 25
= 447

Number of tickets sold
= 1188 + 447
= 1635

Number of tickets left unsold
= 2673 - 1635
= 1038

Answer(s): 1038