[問題]GWD3-33

[cmuboys]

Can someone tell me why the answer is C?
Q33: (什麼東西嘛，機車題)
150, 200, 250, n

Which of the following could be the median of the 4 integers listed above?

I. 175
II. 215
III. 235

A. I only
B. II only
C. I and II only
D. II and III only
E. I, II, and III

[waleaaa]

　　　150　　200　　　250　　
--------|--------|--------|-------＞（它是數線）
　 A　　B　C　　D　E　　F　　G
假設 median = x
當n=A　x = 175
　n=B　x = 175
　n=C　x = (C+200)/2
　n=D　x = 200
　n=E　x = (200+E)/2
　n=F　x = 225
　n=G　x = 225
已知I為答案之一，另由選項反推─
IF x = 215 則 E+200 = 2x = 430 --> E = 230 (介於200~250 OK!)
IF x = 235 則 E+200 = 2x = 470 --> E = 270 (NG!)
所以只有 I & II 正確，故選C