The drama centre had 777 seats. There were 25% fewer $40-seats than $10-seats. 50% of the $10-seats and some $40-seats were sold. A total of $16940 was collected. How many seats were unsold?

	$40	$10	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 = 777

1 u = 777 ÷ 7 = 111

Total number of $10-seat tickets
= 4 u
= 4 x 111
= 444

Number of $10-seat tickets sold
= 50% x 444
= ⁵⁰₁₀₀ x 444
= 222

Amount collected from $10-seat tickets sold
= 222 x 10
= $2220

Amount collected from $40-seat tickets sold
= 16940 - 2220
= $14720

Number of $40-seat tickets sold
= 14720 ÷ 40
= 368

Number of tickets sold
= 222 + 368
= 590

Number of tickets left unsold
= 777 - 590
= 187

Answer(s): 187