The auditorium had 2048 seats. There were 40% fewer $45-seats than $20-seats. 75% of the $20-seats and some $45-seats were sold. A total of $33510 was collected. How many seats were unsold?

	$45	$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 = 2048

1 u = 2048 ÷ 8 = 256

Total number of $20-seat tickets
= 5 u
= 5 x 256
= 1280

Number of $20-seat tickets sold
= 75% x 1280
= ⁷⁵₁₀₀ x 1280
= 960

Amount collected from $20-seat tickets sold
= 960 x 20
= $19200

Amount collected from $45-seat tickets sold
= 33510 - 19200
= $14310

Number of $45-seat tickets sold
= 14310 ÷ 45
= 318

Number of tickets sold
= 960 + 318
= 1278

Number of tickets left unsold
= 2048 - 1278
= 770

Answer(s): 770