Problems 51-58
Problems 51 and 52 are done using the number of subsets theorem, as shown in Examle 7.
Problems 53-55 are done as shown in Example 5.
Problems 56-58 are done like 53-55 where "heads" is the same as "boys" and "tails" is
the same as "girls."
Note: Homework Hints are given only for the levels 1 and 2 problems.