QYQ Set 5-17

[lucyyeh]

If Carmen had 12 more tapes, she would have twice as many as tapes as Rafael. Does Carmen have fewer tapes than Rafael?

1. Rafael has more than 5 tapes
2. Carmen has fewer than 12 tapes

答案是B

可是我選D ... 我覺得兩個條件都可以...不知道哪裡想錯了?
由題目

C + 12 = 2R

1.條件 R>5

用 R=6, C=0
R=7 C=2
.....................
接者不管怎麼代下去，R都比C大

[dibert8]

(C, R) = (0, 6), (2, 7), ... , (12, 12), (14, 13), ...
當 C = 12 時, C = R; 當 C > 12 時, C > R.
所以 C < 12 確保 C < R.