Ican't figure this out for the life of me, and google has nothing. any ideas? at last count, there were over 2,300,534 of these in the us. while you can't see them, chances are pretty good you passed over 150 of them so far today. what are they?

Anut store normally sells cashews for? $4.00 per pound and peanuts for? $1.50 per pound. but at the end of the month the peanuts had not sold? well, so, in order to sell 40 pounds of? peanuts, the manager decided to mix the 40 pounds of peanuts with some cashews and sell the mixture for $2.00 per pound. how many pounds of cashews should be mixed with the peanuts to ensure no change in the? profit?