A sample of part-time students were asked how many courses they are taking during this term. The incomplete results are shown below:
Number of courses taken Frequency Relative Frequency Cumulative Relative Frequency
1 16 0.4 ?
2 20 ? ?
3 ? ? ?
a. Fill in blanks in the table.
b. What percent of students take exactly two courses?
c. What percent of students take one or two courses?