The auditorium had 1152 seats. There were 20% fewer $50-seats than $10-seats. 80% of the $10-seats and some $50-seats were sold. A total of $24270 was collected. How many seats were unsold?

	$50	$10	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 = 1152

1 u = 1152 ÷ 9 = 128

Total number of $10-seat tickets
= 5 u
= 5 x 128
= 640

Number of $10-seat tickets sold
= 80% x 640
= ⁸⁰₁₀₀ x 640
= 512

Amount collected from $10-seat tickets sold
= 512 x 10
= $5120

Amount collected from $50-seat tickets sold
= 24270 - 5120
= $19150

Number of $50-seat tickets sold
= 19150 ÷ 50
= 383

Number of tickets sold
= 512 + 383
= 895

Number of tickets left unsold
= 1152 - 895
= 257

Answer(s): 257