Part A According to this two-way frequency table, how many 9th graders like rock?

Rock Rap Totals
Grade 9 ? 6 10
Grade 10 30 10 40
Totals 34 16 50

number of 9th graders who like rock =

Part B
What percent of the students in Part A are 10th graders?
A. 90%
B. 80%
C. 20%
D. 10%
Part C
Complete the table for the conditional relative frequencies.

Rock Rap Totals
Grade 9 40% 60% 100%
Grade 10 ? ? 100%
Totals 68% 32% 100%