The table shows many students the Head teacher selects when doing a stratified sample by year group of 80 students. There are a total of 560 students in the schoolYear GroupSample sizeTotal no. of studentsYear 727aYear 810bYear 917cYear 1021dYear 115e

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?