I do not get this concept at all! I have seen the videos multiple times and this is just too confusing. Can you explain it or explain an easier way?
Please help
Prime number is the key concept for this type of question
A number is not a factor of n! if:
- It contains a prime factor greater than n, or
- Its factorization requires more occurrences of a prime than n! provides.
Example 1:
14 cannot be a factor of 6!
Because 14 = 7 * 2 and 7 is a prime number bigger than 6
Example 2:
49 cannot be a factor of 13!
Because 49 = 7 * 7 therefore we need 2 occurrences of 7 in n!
While 13 is bigger than 7, 13! has only 1 occurrence of 7.
On the other hand, 49 is a factor of 14! because 14! has 2 occurrence of 7 (7 and 14)
DID NOT understand at all! Made it more complex if anything
Share a question from this topic that you find difficult to solve and I will give a detailed solution. Maybe that will help.