Question

Find which of the following numbers are primes :

(i) 87
(ii) 89
(iii) 63
(iv) 91

Please solve this with explanation!
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Answer 1

Answer:

1. No, 87 is not a prime number. The number 87 is divisible by 1, 3, 29, 87. For a number to be classified as a prime number, it should have exactly two factors. Since 87 has more than two factors, i.e. 1, 3, 29, 87, it is not a prime number.

2. Yes, 89 is a prime number. The number 89 is divisible only by 1 and the number itself. ... Since 89 has exactly two factors, i.e. 1 and 89, it is a prime number.

3. No, 63 is not a prime number. The number 63 is divisible by 1, 3, 7, 9, 21, 63. ... Since 63 has more than two factors, i.e. 1, 3, 7, 9, 21, 63, it is not a prime number.

4. No, 91 is not a prime number. The number 91 is divisible by 1, 7, 13, 91. For a number to be classified as a prime number, it should have exactly two factors. Since 91 has more than two factors, i.e. 1, 7, 13, 91, it is not a prime number.

Answer 2

Answer:

Prime number = Number that is Divisible only number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).

Step-by-step explanation:

87 is not a prime number because it no divisible only number that is divisible only by itself and 1

89 is prime number

63 is not prime number

91 is not prime number