ce math 2008&2009

plz show your working!
Q1.the marked price of a bag is $900. If the bag is sold at the marked price, then the percentage profit is 50%. If the bag is sold at a 20% discount on the marked price,then the profit is?

Q2. If a dictionary is sold at its marked price,then the percentage profit is 30%. If the dictionary is sold at a 20% discount on its marked price, then the profit is $5. Find the cost of the dictionary.