Tailor and Trousers
David is a tailor. He buys two kinds of cloth materials for school uniforms, shirt material which costs him $50 per metre and trouser material which costs him $90 per metre. For every 3 metres of the shirt material he buys 2 metres of the trouser material. He sells the material at a profit of 12%(shirt material) and 10%(trouser material). His total sale is $36,600 (pretty much indeed). Can you find the amount of trouser material he bought (in metres)?