Suppose you work for a large coffee distributor that has a secret coffee blend it sells to local stores. you mix the mexican shade grown blend with the rift valley blend, but always in the same proportion. yesterday, you mixed 80 pounds of the mexican shade grown blend with 24 pounds of the rift valley blend. today, there is 60 pounds of the mexican shade grown coffee left in stock. how many pounds of the rift valley coffee should you mix with it to get your secret blend?