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Deux Digit Deduction (Posted on 2015-01-21) Difficulty: 3 of 5
X = 99, Y = 9X and Z = 9Y

Find the respective last two digits of Y and Z.

No Solution Yet Submitted by K Sengupta    
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Solution powerful solution | Comment 1 of 2
The last two digits of powers of 9 have a cycle of length 10, so you only need the last digit of the exponent to know the last two digits of the power.

Since 9^9 ends in 89
Y also ends in 89
and so
Z also ends in 89.

  Posted by Jer on 2015-01-21 12:25:04
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