fauji wrote:
What is the smallest non-prime positive integer that is not a factor of 5040 ?
A) 7
B) 8
C) 11
D) 12
E) 22
As soon as i saw the question i picked up my pen and started using divisibility rules starting from 3 and went upto 12.
When i finally looked up, i saw the answers and cursed myself, ALOT!
7,11 are primes, hence out of the question.
All you need to check is div by 4, 3 & 8, which will hardly take 15 sec and you'll have your answer!
Conclusion : ALWAYS SEE/CHECK ANSWER CHOICES BEFORE GOING LOOKING FOR SOLUTIONS IN YOUR SCRATCHPAD.
DON'T BE AN OSTRICH, BE SMART!