Question

(7) Which of the following statement is TRUE?

(A) If am−1 ≡ 1 (mod m), then by Fermat’s Little Theorem m must be a prime.

(B) If ac ≡ bc (mod m), then a ≡ b (mod m).

(C) If a ≡ b (mod m) and n | m, then a ≡ b (mod n).

(D) If 2n −1 is a prime, then 2n−2(2n −1) is a perfect number.

(E) If p is a prime, then 2p −1 is also a prime.

(F) If a ≡ b (mod m1) and a ≡ b (mod m2), then a ≡ b (mod m1m2) .

Answer 1