For each of the following, find the percent change in the volume of a cube. The length of the side of the cube was first increased by 50% and then decreased by 20%.

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?