The theatre had 1544 seats. There were 40% fewer $25-seats than $15-seats. 60% of the $15-seats and some $25-seats were sold. A total of $19660 was collected. How many seats were unsold?

	$25	$15	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 = 1544

1 u = 1544 ÷ 8 = 193

Total number of $15-seat tickets
= 5 u
= 5 x 193
= 965

Number of $15-seat tickets sold
= 60% x 965
= ⁶⁰₁₀₀ x 965
= 579

Amount collected from $15-seat tickets sold
= 579 x 15
= $8685

Amount collected from $25-seat tickets sold
= 19660 - 8685
= $10975

Number of $25-seat tickets sold
= 10975 ÷ 25
= 439

Number of tickets sold
= 579 + 439
= 1018

Number of tickets left unsold
= 1544 - 1018
= 526

Answer(s): 526