Figure 4 gives the responses of a group of randomly selected college freshmen when asked for the

Question:

Figure 4 gives the responses of a group of randomly selected college freshmen when asked for the types of placement tests taken. A total of 82 placement tests were taken. The number of mathematics placement tests taken was 2 more than twice the number of writing placement tests taken. Eight more writing placement tests were taken than reading placement tests. Determine the values of x, y, and z in Fig. 4.
Figure 4 Type of Placement Tests Taken