Remember that bustard 2 is both even and prime!jnellaz wrote:Is interger A a prime number?
1. 2A has exactly 3 factors.
2. A is an even number
Answer is A[spoiler][/spoiler]
Prime Number DS
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logitech
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cramya
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Is interger A a prime number?
1. 2A has exactly 3 factors.
2. A is an even number
Take the easier(strictly my opinion) of the 2 statements
Stmt II A is a even number
2 is even and prime (only even prime)
4 is even and not prime
INSUFF
Down to choices A C E
Stmt II
2A has exactly 3 factors.
Juts like primes have only 2 factors(1 and itself); only squares of primes(like 4 = 2 ^ 2, 9 = 3 ^ 2) have exactly 3 factors (distinct)
When u multiply something by 2 that product is EVEN (comes in handy in lot of problems i.e may not be given when u see something multiplied by 2 we must immediately leep this in mind as it may be helpful)
The only square of a prime that is even and has 3 factors is 4 so A=2 and is Prime
SUFF
A)
Hope I have not missed something here! Good luck and let me know if u have questions.
