Pham is conducting a survey for the school newspaper. He surveyed students at his school and found that students had the new Phone, students had a Pad computer, and students had neither. Pham then made a Venn diagram to illustrate the information. How did Pham determine the number of students who have both Phones and Pads? How many students have Phones or Pads? How did he find this? Recall that students had the new Phone and students had a Pad. Why cannot Pham just add to get the answer to part (b)? Explain.