Well done, what is left?

Number Theory Level 2

Find the number of positive integers $n$ in the range of $12\leq n \leq 40$ such that $(n-1)!$ is not divisible by $n$ .

3 solutions

Manasa Veena
Oct 4, 2014

yesss!!! no of primes between 12-40 will do it..it is 7...have fun!!!!!

Piyush Maheshwari
Sep 30, 2014

We know, The product will not be divisible by n when n is prime no.Thus there are 7 prime no. between12& 40.

Mahmoud Sayed
Jun 13, 2015

Just count the number of prime numbers in the given range! { 13, 17, 23, 29, 31, 37, 39}