Given the frequency table, what percentage of the students that like rock are also in grades 11-12? Round to the nearest whole percent.

Band Preference for School Dance

Rap Rock Country Row totals

Grades 9-10 40 30 55 125

Grades 11-12 60 25 35 120

Column totals 100 55 90 245

a. 10%

b. 21%

c. 25%

d. 45%

Answer: d. 45%

Step-by-step explanation:

According to the frequency table there are 30 sudents who like rock in grades 9-10 and 25 students that like rock and are in grades 11-12.

25 : 55 = n : 100

25 · 100 = 55 · n

2500 : 55 = n n = 45.454545 n = 45%

55 is the total amount of students that like rock

25 is the total amount of students that like rock in grades 11-12

100 is the total percentage

d. 45%

Step-by-step explanation:

In total there are 30 + 25 = 55 students in total that like rock. From these there are 25 who are in grades 11-12. This makes that (25/55) * 100% = 45.45% of the students that like rock are in grades 11-12.