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UPSC 2013 CDS 2 Math Paper
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© examsnet.com
Question : 27
Total: 100
Every prime number of the form
3
k
+
1
can be represented in the form
6
m
+
1
(k, m are integers) when
[2013 CDS-II]
k is odd
k is even
k can be both odd and even
No such form is possible
Validate
Solution:
Any prime number greater than 3 is odd number in the form of
2
m
+
1
Now
3
k
+
1
=
2
n
+
1
⇒
n
=
3
and
k
=
2
∴ Every prime number of the form 3k +1 can be represented in the form
6
m
+
1
© examsnet.com
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