hello everyone...(Hi)

I have a quation here says

Bulldust Inc. blends silicon and nitrogen to produce two types of fertiliser. Fertiliser 1

must be at least 40% nitrogen and sells for $20/kg. Fertiliser 2 must be at least 70%

silicon and sells for $18/kg. Bulldust can purchase up to 800 kg of nitrogen at $10/kg and

up to 1000 kg of silicon at $8/kg. Assuming that all fertiliser produced can be sold,formulate an LP to help Bulldust maximize profit.

Ive tried so many different ways but still cant get the right answer..(Headbang) could please someone help me answering this question

thanks.