How is this done

3) A statistics teacher has 40 students in his class, 23 females and 17 males. At the beginning of class on Monday, the teacher planned to spend time reviewing an assignment due that day. Unknown to the teacher, only 19 of the females and 11 of the males had completed the assignment. The teacher plans to randomly select students to do problems from the assignment on the board. a) Create a tree diagram or a two-way table to model this random process. b) What is the probability that a randomly selected student has completed the assignment? Show your work