The number of positive integers n in the range 12 ≤ n ≤ 40 such that the product
(n − 1)(n − 2)...3.2.1 is not divisible by n is
Choose one:	A) 5	B) 7	C) 13	D) 14	E) 16
Explanation :   (n-1)! is always divisible by n unless and untill n is a prime number   e.g.(5-1)!=4! which is not divisible by 5 bcuz 5 is a prime number   Therefore, find all prime numbers in the range of 12 to 40 i.e   13, 17, 19, 23, 29, 31 and 37   Hence, the number of positive integers n is 7.   Answer : 7
<result>B</result>
The number of positive integers n in the range 12 ≤ n ≤ 40 such that the product
(n − 1)(n − 2)...3.2.1 is not divisible by n is