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%

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.

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

2 x t divided by n

step-by-step explanation: