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A seven digit number .........

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A seven digit number .........

by pzazz12 » Fri Oct 22, 2010 3:41 am
A seven digit number is such that both its first and last digits are 1 and the rest of the digits are zero except for the middle digit.Also,the number is divisible by 13.What is the middle digit?

A.3
B.2
C.1
D.4
E.None of these
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by Rahul@gurome » Fri Oct 22, 2010 4:07 am
pzazz12 wrote:A seven digit number is such that both its first and last digits are 1 and the rest of the digits are zero except for the middle digit.Also,the number is divisible by 13.What is the middle digit?

A.3
B.2
C.1
D.4
E.None of these
Say the middle digit is N => The number is 100N001
Image

Now, if N = 1, the division terminates with remainder 1.
Image

If N = 2,
Image

Hence the middle digit is 2.

The correct answer is B.
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