Official papers

Official 2018 Paper 2 · Q12

Paper 2Logic & proofNumber & counting

Consider the following statement:

For any positive integer NN there is a positive integer KK such that N(Km+1)−1N(Km+1)-1 is not prime for any positive integer mm.

Which one of the following is the negation of this statement?

AFor any positive integer NN there is a positive integer KK such that there is a positive integer mm for which N(Km+1)−1N(Km+1)-1 is prime.
BFor any positive integer NN there is a positive integer KK such that there is a positive integer mm for which N(Km+1)−1N(Km+1)-1 is not prime.
CFor any positive integer NN there is a positive integer KK such that for any positive integer mm, N(Km+1)−1N(Km+1)-1 is not prime.
DFor any positive integer NN, any positive integer KK and any positive integer mm, N(Km+1)−1N(Km+1)-1 is not prime.
EThere is a positive integer NN such that for any positive integer KK there is a positive integer mm for which N(Km+1)−1N(Km+1)-1 is not prime.
FThere is a positive integer NN such that for any positive integer KK there is a positive integer mm for which N(Km+1)−1N(Km+1)-1 is prime.
GThere is a positive integer NN such that for any positive integer KK and any positive integer mm, N(Km+1)−1N(Km+1)-1 is prime.
HThere is a positive integer NN and a positive integer KK for which there is no positive integer mm for which N(Km+1)−1N(Km+1)-1 is prime.

Read the questions freely. Sign in to check your answer, see the worked solution and save your progress.