Answers

2014-04-17T13:24:37+08:00
{a}, {e},{i}, {o},{u}, {a,e}, {a,i}, {a,o} , {a,u} , {e,i} , {e,o}, {e,u}, {i,o} , {i,u}, {o,u},{}
7 3 7
2014-04-21T15:13:26+08:00
There would be 32 possible subsets. These are:
{}, {a}, {e}, {i}, {o}, {u}, {ae}, {ai}, {ao}, {au}, {ei}, [eo}, {eu}, {io}, {iu}, {ou}, {aei}, {aeo}, {aeu}, {aio}, {aiu}, {aou}, {eio}, {eiu}, {eou}, {iou}, {aeio}, {aeiu}, {aeou}, {aiou}, {eiou}, {aeiou}. 
25 4 25