請教maths問題

1.an alloy is made of copper and iron by weight.42% of it is copper and the rest is iron, if the alloy weighs 55kg, find the weighs of copper and iron.2. the school used 14% of school grant to buy an electronic whiteboard.the whiteboard costs $13350. find the amount of school grant.3.after210ml of orange juicd is poured into a glass, there is still 40% of space left, find the capacity of the glass.請詳細列式thankyou very much!!!