Find the next number in the pattern:

1) 45, 39, 33, 27, 21, 15,

2) 486, 162, 54, 18,

3) 500, 100, 20,

Afrequency table of grades has five classes (a, b, c, d, f) with frequencies of 3, 13, 14, 5, and 3 respectively. using percentages, what are the relative frequencies of the five classes?