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

  • question_answer
    The number, \[{{4}^{n}}\], where n is a natural number, ends with the digit 0 for any natural number n.

    A) True

    B) False

    C) Can't say

    D) Partially True/False

    Correct Answer: B

    Solution :

    Given, n is a natural number. Let us assume dial \[{{4}^{n}}\]ends with 0, thus \[{{4}^{n}}\] is divisible by 2 and 5 both.
    But prime factors of 4 are \[2\times 2\].
    \[\therefore {{4}^{n}}={{\left( 2\times 2 \right)}^{n}}={{2}^{2n}}\]
     Thus. prime factorisation of \[{{4}^{n}}\] does not contain 5. So, the fundamental theorem of arithmetic guarantees that there are no other primes in the factorisation of \[{{4}^{n}}\].
    So, our assumption that \[{{4}^{n}}\]ends with 0 is wrong.
     


You need to login to perform this action.
You will be redirected in 3 sec spinner