Which of the following statements are true ? (i) If a number is divisible by 3, it must be divisible by 9. (ii) If a number is divisible by 9, it must be divisible by 3. (iii) If a number is divisible by 4, it must be divisible by 8. (iv) If a number is divisible by 8, it must be divisible by 4. (v) A number is divisible by 18, if it is divisible by both 3 and 6. (vi) If a number is bivisible by both 9 and 10, ut nyst be divisible by 90. (vii) If a number exactly divides the sum of two numbers, it must exactly divide the numbers separately. (viii) If a number divides three numbers exactly, it must divede their sum exactly. (ix) If two numbers are co-prime , at least one of them must be a prime number. (x) The sum of two consecutive odd numbers is always divisible by 4.