There were 280 T-shirts at a shop. ⁵₇ of them were with collars. T-shirts with collars were priced at $9 each. T-shirts without collars were priced at $11 each. The shop owner sold ¹₂ of the T-shirts with collars and ⁴₅ of the T-shirts without collars. How much did he collect from all the T-shirts he sold?
Number of T-shirts = 7 u

7 u = 280

1 u = 280 ÷ 7 = 40

Number of T-shirts with collars
= 5 u
= 5 x 40
= 200

Number of T-shirts with collars sold 
= ¹₂ x 200
= 100

Number of T-shirts without collars
= 2 u
= 2 x 40
= 80

Number of T-shirts without collars sold
= ⁴₅ x 80
= 64

Amount that the shop owner collected from the sale of the T-shirts with collars
= 100 x 9
= $900

Amount that the shop owner collected from the sale of the T-shirts without collars
= 64 x 11
= $704

Total amount that the shop owner collected from all the T-shirts he sold
= 900 + 704
= $1604

Answer(s): $1604