You can put this solution on YOUR website! First you have to multiply 42 by 20. Because you have to find the total cost of the whole bag. Then a little guess and check you would get 16 lb of green tea and 4 lb of herbal tea. They both have to equal 20 lbs and $840. Multiply 16 by 40 then 50 by 4 then add them together you will get 840.