300 students in the 9th, 10th, and 11th grades were asked if they have a job. the results are shown in the two-way frequency table. what percent of the 11th graders have a job?

Only focus on the "11 graders" row. There are 48 of these students who have a job out of 80 total. 

So,
48/80 = 0.6
which converts to 60% after you move the decimal point two spots to the right.

This means 60% of the eleventh graders have a job

60%