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Sam has forgotten his friend's seven-dig...

Sam has forgotten his friend's seven-digit telephone number. He remembers the following: the first three digits are either 635 or 674, the number is odd, and the number nine appears once, what is the minimum number of trials he has to make before he can be certain to succeed?

A

10000

B

3402

C

3200

D

5000

Text Solution

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The correct Answer is:
B
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