10th Class Mathematics Real Numbers Question Bank MCQs - Real Number

  • question_answer
    \[{{12}^{n}}\]ends with the digit 0 or 5 for natural number n

    A) 2

    B) 3

    C) No value

    D) 5

    Correct Answer: C

    Solution :

    If any number ends with the digit 0 or 5, it is always divisible by 5. If \[{{12}^{n}}\]ends with Adie digit zero it must be divisible by 5. This is possible only if prime factorization of \[{{12}^{n}}\]contains the prime number 5. Now,
    \[12=2\times 2\times 3={{2}^{2}}\times 3\]
    \[\Rightarrow \,\,{{12}^{n}}={{\left( {{2}^{2}}\times 3 \right)}^{n}}={{2}^{2n}}\times {{3}^{n}}\]
     [since, there is no term contains 5] Hence, there is no value of n e N for which \[{{12}^{n}}\]ends with digit zero or five.
     


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