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题库 / OG2018Q-DS-281
If ~$N$~ is positive odd integer, is ~$N$~ prime?
(1) ~$N =2^k+1$~ for some positive integer ~$k$~.
(2) ~$N $~= 2 and ~$N$~ +4 are both prime.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
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N = 9