Hello, I need help figuring out how to solve 9 and 10. I know the answers are C for 9 and B for 10 I just don't know how my teacher got that.

9) Consider the feasible set (FS) below of a certain linear programming problem. 9) E (2. 4) D (4. 4) FS A (2. 2) BEBJJ C(4,1) What is the maximum value of the objective function 5x - y? A) - 40 B) 30 C) 19 D) 0 E) none of these A coffee merchant sells two blends of coffee. Each pound of blend A contains 80% Mocha Java and 20 % Jamaican and sells for $2 a pound. Each pound of blend B contains 35% Mocha Java and 65% Jamaican and sells for $2.25 a pound. The merchant has available 1000 pounds of Mocha Java and 600 pounds of Jamaican. The merchant will try to sell the amount of each blend that maximizes her income. Let x be the number of pounds of blend A and y be the number of pounds of blend B. 10) Since the merchant above has available 1000 pounds of Mocha Java, one inequality that must be 10) satisfied is A) 0.35x + 0.65y a 1000. B) 0.8x + 0.35y s 1000. C) 0.8x + 0.35y a 1000. D) 0.8x + 0.2y s 1000. E) none of these