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    Question

    If ‘742x319’ is a seven-digit number that is exactly

    divisible by 72, then what is the digit ‘x’?
    A 1 Correct Answer Incorrect Answer
    B 5 Correct Answer Incorrect Answer
    C 2 Correct Answer Incorrect Answer
    D 5 Correct Answer Incorrect Answer

    Solution

    ATQ,

    A number divisible by 72 must be divisible by both 8 and 9.

    To be divisible by 9, the sum of digits must be divisible by 9.

    Sum of digits = 7 + 4 + 2 + x + 3 + 1 + 9 = (26 + x)

    We need 26 + x to be divisible by 9.

    Trying values:

    26 + x = 27 → divisible by 9

    ⇒ x = 1

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