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    Question

    For how many positive integral values of 'p', the number

    '78292p' is divisible by 12?
    A 1 Correct Answer Incorrect Answer
    B 2 Correct Answer Incorrect Answer
    D 3 Correct Answer Incorrect Answer

    Solution

    For a number to be divisible by 12, it must be divisible by both 3 and 4.

    Divisibility of 3: Sum of each digit of the number must be divisible by 3.

    Divisibility of 4: Last two digits of the number must be divisibly by 4.

    Last two digits of 78292p = 2p

    So, 'p' must be 0, 4 or 8 because only 20, 24 and 28 are divisibly by 4.

    Sum of each digit of the number = 7 + 8 + 2 + 9 + 2 + p = 28 + p

    When 'p' = 0: sum of digits = 28 + 0 = 28 which is not divisibly by 3. So, 'p' = 0 is not valid.

    When 'p' = 4: sum of digits = 28 + 4 = 32 which is not divisibly by 3. So, 'p' = 4 is not valid.

    When 'p' = 8: sum of digits = 28 + 8 = 36 which is divisibly by 3. So, 'p'= 8 is valid.

    Therefore, for only 1 value of 'p', the given number is divisibly by 12.

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