Please answer Parts C & D

c) Suppose Bob's utility for goods 1 and 2 is given by U(X1, X2) = X1 + X2. Bob's income is $200, the price of good 1 is $20 and the price of good 2 is $10. At Bob's optimal bundle, how many units of each good will Bob purchase? d) Suppose all consumers face the same prices for goods 1 and 2, that all consumers have convex preferences, and that each consumer is choosing their most preferred bundle (i.e., their optimal bundle). What do we know about the MRS for all consumers who purchase goods 1 and 2? Explain