State whether the following statements are true or false. If a statement is false, justify your answer:

(i) The sum of two prime numbers is always an even number.

(ii) The sum of two prime numbers is always a prime number.

(iii) The sum of two prime numbers can never be a prime number.

(iv) No odd number can be written as the sum of two prime numbers.

(v) If two numbers are co-prime, then atleast one of them must be prime.

(vi) If a number is divisible by 18, it must be divisible by 3 and 6 both.

(vii) If a number is divisible by 2 and 4 both, it must be divisible by 8.

(viii) If a number is divisible by 3 and 6 both, it must be divisible by 18.

(ix) HCF of an even number and an odd number is always 1.

All factors of 6 are

1. 1, 6

2. 2, 3

3. 1, 2, 3

4. 1, 2, 3, 6

The number of even numbers between 68 and 90 is

1. 10

2. 11

3. 12

4. 31

Which of the following is a prime number?

1. 69

2. 87

3. 91

4. 97