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ITMC 2018 Grade 9 National Preliminary set01 Question 23

ITMC · ITMC 2018 Grade 9 National Preliminary set01

Question 23

For a nonnegative integer $n$, $n!$ is the product of all positive integers at most $n$, with $0!=1$. Examples: $1!=1,2!=2,3!=6,4!=24$. How many primes are among the 28 numbers $30!+2,30!+3,\ldots,30!+29$?
  1. 5
  2. 10
  3. 15
  4. 28
  5. None of these.