Question

Which of the following statements are correct?i.All numbers which are divisible by 4 must also be divisible by 8. ii. If two numbers are co-primes, at least one of them must be prime .a)Only (i) is correct b) Only (ii) is correct c) Both are correct d) None is correct

Answer 1

Answer:

i.All numbers which are divisible by 4 must also be divisible by 8

Answer 2

Answer:

(a) If a number is divisible by 3, it must be divisible by 9.

False. We can prove it with the help of an example. 12 is divisible by 3 but it is not divisible by 9.

(b) If a number is divisible by 9, it must be divisible by 3.

True. If a given number is divisible by some number then it is also divisible by its factor.

(c) A number is divisible by 18, if it is divisible by both 3 and 6.

False. 12 is divisible by both 3 and 6 but it is not divisible by 18.

(d) If a number is divisible by 9 and 10 both, then it must be divisible by 90.