If a student may do more than one​ job, then what is the probability that the instructor will choose at least one boy to do the​ jobs?

Question

26) Refer to the demographic information shown to the right that has been collected by an instructor after surveying her class.

The instructor randomly chooses one student to pass out​ papers, one student to clean the​ chalkboard, and one student to empty the trash. If a student may do more than one​ job, then what is the probability that the instructor will choose at least one boy to do the​ jobs?

Question content area top right

Part 1

Total number of students in the class	50		Number of boys	18
Number of girls	32
Number of Freshman	6
Number of Sophomores	16
Number of Juniors	13
Number of Seniors	15

There is a _ % probability that the instructor will choose at least one boy to do the jobs.

​(Round the final answer to one decimal place as needed. Round all intermediate values to three decimal places as​ needed.)

Answer 1

This is a binomial density problem with p=.36 (18/50) and q=.64 (32/50).

The probability of at least one boy among the 3 chosen is 1- probability of all girls, that is

1-(.64)³.