涛涛26--14

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sigrid920

楼主

发表于 2006-11-1 02:48:00 | 只看该作者

涛涛26--14

Q14:

A three-digit code for certain logs uses the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 according to the following constraints. The first digit cannot be 0 or 1, the second digit must be 0 or 1, and the second and third digits cannot both be 0 in the same code. How many different codes are possible?

A. 144

B. 152

C. 160

D. 168

E. 176

请教思路~~!!谢谢~~!!