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Real Numbers

Question
CBSEENMA10006151

Consider the number 12n, where n is a natural number. Check whether there is any value of n ∊ N for which 12n ends with the digit zero.

Solution

We know, if any number ends with the digit zero it is always divisible by 5.

⇒ If 12n ends with the digit zero, it must be divisible by 5.

This is possible only if prime factorisation of 12n contains the prime number 5.

Now, 12 = 2 × 2 × 3 = 22 × 3

⇒ 12n = (22 × 3)n = 22 × 3n

i.e., prime factorisation of 12' does not contain the prime number 5.

⇒ There is no value of n ∊ N for which 12n ends with the digit zero.