The auditorium had 1344 seats. There were 25% fewer $50-seats than $15-seats. 50% of the $15-seats and some $50-seats were sold. A total of $26410 was collected. How many seats were unsold?

	$50	$15	Total
Number	3 u	4 u	7 u

100% - 25% = 75%
⁷⁵₁₀₀ = ³₄

Total number of seats
= 3 u + 4 u
= 7 u

7 u = 1344

1 u = 1344 ÷ 7 = 192

Total number of $15-seat tickets
= 4 u
= 4 x 192
= 768

Number of $15-seat tickets sold
= 50% x 768
= ⁵⁰₁₀₀ x 768
= 384

Amount collected from $15-seat tickets sold
= 384 x 15
= $5760

Amount collected from $50-seat tickets sold
= 26410 - 5760
= $20650

Number of $50-seat tickets sold
= 20650 ÷ 50
= 413

Number of tickets sold
= 384 + 413
= 797

Number of tickets left unsold
= 1344 - 797
= 547

Answer(s): 547