Hailey would like to make a 5 lb coffee mixture that is 60% sumatra coffee bean blend. she has several pounds of a mixture that is 20% sumatra beans and another mixture blend with 80% sumatra beans . let x represent the amount of the 20% blend and y represent the amount of the 80% blend to find out how many pounds of each mixture hailey will need. (a) what is the system that models this situation? (b) what is the solution to the system: show your work.