How many divisors does positive integer N have?
1. The difference between the largest and the smallest divisor of N is 21
2. N+1 has 2 divisors
OA is A
Divisibility problem
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- anshumishra
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Statement 1:tonebeeze wrote:How many divisors does positive integer N have?
1. The difference between the largest and the smallest divisor of N is 21
2. N+1 has 2 divisors
OA is A
Sufficient
Please note that the largest divisor is the number itself (and smallest is 1), so we know the number.
Statement 2:
Insufficient
you can check with different values of n, that thsi will give different results.
Hence, A
Thanks
Anshu
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Anshu
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- Anurag@Gurome
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Statement 1: The difference between the largest and the smallest divisor of N is 21tonebeeze wrote:How many divisors does positive integer N have?
1. The difference between the largest and the smallest divisor of N is 21
2. N+1 has 2 divisors
Largest divisor of any positive integer is the integer itself and smallest divisor of any positive integer is 1. Thus, (Integer - 1) = 21 => The integer is 22. We can easily determine the number of divisors of 22.
Sufficient.
Statement 2: N+1 has 2 divisors
This implies (N + 1) is a prime. But there is infinite number of positive integers N such that (N + 1) is prime.
Not Sufficient.
The correct answer is A.
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