The auditorium had 1176 seats. There were 40% fewer $50-seats than $20-seats. 60% of the $20-seats and some $50-seats were sold. A total of $24270 was collected. How many seats were unsold?

	$50	$20	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 = 1176

1 u = 1176 ÷ 8 = 147

Total number of $20-seat tickets
= 5 u
= 5 x 147
= 735

Number of $20-seat tickets sold
= 60% x 735
= ⁶⁰₁₀₀ x 735
= 441

Amount collected from $20-seat tickets sold
= 441 x 20
= $8820

Amount collected from $50-seat tickets sold
= 24270 - 8820
= $15450

Number of $50-seat tickets sold
= 15450 ÷ 50
= 309

Number of tickets sold
= 441 + 309
= 750

Number of tickets left unsold
= 1176 - 750
= 426

Answer(s): 426