How to solve?

90 adults with gum disease were asked the number of times per week they used to floss before their diagnoses. The (incomplete) results are shown below: # of times floss per week Frequency Relative Frequency Cumulative Frequency O 13 13 8 0.0889 21 18 0.2 IN 9 0.1 48 4 0.1444 61 0.1 70 6 0.0889 78 7 12 0. 1333 90 a. Complete the table (Use 4 decimal places when applicable) b. What is the cumulative relative frequency for flossing 3 times per week