Question

    Find the sum of all the possible values of 'a' such that

    '9a5784' is always divisible by 3.
    A 21 Correct Answer Incorrect Answer
    B 12 Correct Answer Incorrect Answer
    C 18 Correct Answer Incorrect Answer
    D 15 Correct Answer Incorrect Answer

    Solution

    A number is divisible by 3 when sum of its digits is divisible by 3.Sum of digits = 9 + a + 5 + 7 + 8 + 4 = a + 33(a + 33) is divisible by 3 when 'a' = 0, 3, 6 or 9Therefore, required sum = 0 + 3 + 6 + 9 = 18

    Practice Next