There were 150 T-shirts at a shop. ²₅ of them were without collars. T-shirts without collars were priced at $9 each. T-shirts with collars were priced at $12 each. The shop owner sold ¹₃ of the T-shirts without collars and ²₃ of the T-shirts with collars. How much did he collect from all the T-shirts he sold?
Number of T-shirts = 5 u

5 u = 150

1 u = 150 ÷ 5 = 30

Number of T-shirts without collars
= 2 u
= 2 x 30
= 60

Number of T-shirts without collars sold 
= ¹₃ x 60
= 20

Number of T-shirts with collars
= 3 u
= 3 x 30
= 90

Number of T-shirts with collars sold
= ²₃ x 90
= 60

Amount that the shop owner collected from the sale of the T-shirts without collars
= 20 x 9
= $180

Amount that the shop owner collected from the sale of the T-shirts with collars
= 60 x 12
= $720

Total amount that the shop owner collected from all the T-shirts he sold
= 180 + 720
= $900

Answer(s): $900