Question

if a no.is divisible by 3 it must be divisible by 9


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Answer 1

Answer:

Since 9 is divisible by 3, every number divisible by 9 will be also be divisible by 3. This happens because in the divisibility test formula of 9, the sum of the digits should be divisible by 9. If this sum is divisible by 9, it automatically is divisible by 3 since 3 is a factor of 9.

Answer 2

Step-by-step explanation:

Every number divisible by 9 is divisible by 3.For example 7425 is divisible by 9 hence,it is divisible by 3.However a number divisible by 3 is not necessarily divisible by 9.For example 6,12,15,21,24,30 are all divisible by 3 but none of them is divisible by 9.