Jack is deciding how to spend the $6 budget he has allocated for today's telephone calls.  There are only two people he intends to call:  his girlfriend Jill, and his old high school friend, Steve.  Jack's love for Jill is such that he could talk to her forever; the marginal utility of a minute talking to Jill is a constant ten utils, regardless of the number of minutes he talks.  Steve usually has a lot of interesting news, but he becomes dull and boring after awhile; the marginal utility of talking to Steve is given by the equation:

                                                      MU = 60 - 2M

      where M is the number of minutes they have talked so far.  So, the first minute gives Jack 58 utils, the second minute gives him 56 utils, etc.

      It costs 5 cents per minute to call Jill, and 10 cents per minute to call Steve, who lives farther away. 

      How should Jack allocate his budget of $6 to maximize his total utility?  In other words, how many minutes should Jack spend talking to Steve today, and how many minutes talking to Jill?