单选题 The average of x and y is 16 and the average of x, y, and z is 22. What is the value of z?

(A) 16
(B) 22
(C) 34
(D) 45
(E) 66

【正确答案】 C

【答案解析】You are given that the average of x and y is 16. Therefore, (x+y)÷2=16, which means that x+y=32. It is not important to know what x and y equal individually, only to know that their sum is 32. Given that the average of x, y, and z is 22, then (x+y+z)÷3=22, and x+y+z=66. Since x+y=32, then 32+z=66, and z=34.