Question

    Determine the highest possible value of (x + y) if the

    number '3x725y4' is divisible by 12.
    A 23 Correct Answer Incorrect Answer
    B 15 Correct Answer Incorrect Answer
    C 20 Correct Answer Incorrect Answer
    D 12 Correct Answer Incorrect Answer

    Solution

    ATQ,

    A number is divisible by 12 if it’s divisible by both 3 and 4.

    Check last two digits ‘y4’.

    ‘y4’ divisible by 4 → y = 0, 2, 4, 6, 8

    Maximum y = 8

    Now check sum of digits:

    3 + x + 7 + 2 + 5 + 8 + 4 = 29 + x

    29 + x must be divisible by 3 → x = 1, 4, 7

    Maximum x = 7

    So, max (x + y) = 7 + 8 = 15

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