Question

    A number '71945b' is divisible by 6, but not by 5. What is

    the value of (b² + 1)?
    A 17 Correct Answer Incorrect Answer
    B 25 Correct Answer Incorrect Answer
    C 13 Correct Answer Incorrect Answer
    D 10 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Sum = 7 + 1 + 9 + 4 + 5 + b = 26 + b

    We want (26 + b) divisible by 3 and b even (for divisibility by 2), and ≠ 0 or 5.

    Try b = 4 → 26 + 4 = 30

    So, b = 4

    (b² + 1) = 16 + 1 = 17

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