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Help needed OG13 163

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by minkathebest » Sat Nov 10, 2012 3:36 pm
You might need to post the questions because people may not look it up for you.
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by eaakbari » Tue Nov 13, 2012 9:10 am
We need only the unit's digits of both the the expressions (33)^43 & (43)^33 to get units digit of n


A number ending in 3 follows the unit's digit pattern

3 ,9 , 7 , 1 , 3 , 9 ,7.....

(you can quickly obtain the above by multiplying (33) ^ 1 gives 3 as units digit , (33) ^ 2 gives 9 as units digit and so on.)

Hence pattern repeats every 4 numbers

So at (33) ^ 43 units digit will be 7
and at (43)^33 units digit will be 3

Hence n has units digit as 0

Hence A
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