kashishh
If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers?
(1) m is not divisible by 3.
(2) m is not divisible by 5.
OA is A
My doubt is when we analyse stat. 1, aren’t we left with
7,11,13,17,19,23,25,29
out of which isn’t 25 has a different answer to the question than the other numbers?
don’t we need stat. 2 to answer it?
No, since 25 (as well as all other possible values of m from statement (1)), is divisible only by one prime number - 5.
If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers?Since the range is not that big we can write down all possible value of m for each statement.
(1) m is not divisible by 3 --> m can be: 5, 7, 11, 13, 17, 19, 23, 25, and 29. Each has only one
distinct prime in its prime factorization. Sufficient.
(2) m is not divisible by 5 --> m can be: 3, 7, 9, 11, 13, 17, 19, 21, STOP. Each but 21 has one prime in its prime factorization, while 21 has two primes: 3 and 7. Not sufficient.
Answer: A.
Hope it's clear.
Sorry Bunuel but I don't quite get it, we are asked it is divisible by how many different positive prime numbers.
So from Statement 1 I understand that it can be divisible by all of them because they are all distinct prime numbers so that will be 9 numbers
But from Statement 2, I don't understand it that well. OK we have 21 that has two primes 3, and 7 but we had already considered them early in the list, so what's the deal with having them again? Since we are asked for different primes then we just ignore these.