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Which number below is a prime number?A. 73B. 95C. 63D. 72

User SmartyP
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1 Answer

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A prime number is defined as the natural number which is only divisible by 1 and itself.

It cannot have any other factors than 1 and itself.

Consider that according t the divisibility rule of 3, the numbers 63 and 72 both yield a sum of digits as 9 which is divisible by 3, so the numbers 63 and 72 will be divisible by 3. Since there exists a factor other than 1 and the number itself, 63 and 72 cannot be prime numbers.

The number 95 contains 5 at its unit place, so the number will be divisible by 5. This is concluded on the basis of divisibility rule of 5. Since there exists a factor other than 1 and the number itself, 95 cannot be prime number.

The last remaining number 73 has no other factors than 1 and 73, so it can be referred as a prime number.

Therefore, option A is the correct choice.

User Balban
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