integers
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- ankur.agrawal
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- rohit_gmat
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sorry the question is not clear.
Is it 3^(8n + 3 +2) or something else?
What are the Answer choices? Whats the source?
Is it 3^(8n + 3 +2) or something else?
What are the Answer choices? Whats the source?
-
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IMO: 3ankur.agrawal wrote:If n is a positive integer, what is the remainder when 3^8n+3 + 2 is divided by 5?
patterns for 3 squared is: 3,9,7,1.....
so by plugging in # we can find the pattern. for n=1 we'll have 3^13. going back to pattern i just mentioned, u'll find out that the 13th pattern is 3.
plug in 2; it'll output 3^21. go back to pattern and u'll find out once again that the 21st pattern is also 3....
OA?
- arora007
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Guys have a look at this flash card...
https://www.beatthegmat.com/papgust-s-gm ... tml#259476
Unit's place that has digits - 2/3/7/8
Then, unit's digit repeats every 4th value. Divide the power (or index) by 4.
After dividing,
If remainder is 1, unit digit of number raised to the power 1.
If remainder is 2, unit digit of number raised to the power 2.
If remainder is 3, unit digit of number raised to the power 3.
If remainder is 0, unit digit of number raised to the power 4.
effectively, three is raised to three and then two is added,
so (27+2)/5 the remainder should be 4.....whatsay??
https://www.beatthegmat.com/papgust-s-gm ... tml#259476
Unit's place that has digits - 2/3/7/8
Then, unit's digit repeats every 4th value. Divide the power (or index) by 4.
After dividing,
If remainder is 1, unit digit of number raised to the power 1.
If remainder is 2, unit digit of number raised to the power 2.
If remainder is 3, unit digit of number raised to the power 3.
If remainder is 0, unit digit of number raised to the power 4.
effectively, three is raised to three and then two is added,
so (27+2)/5 the remainder should be 4.....whatsay??
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