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    Question

    Out of four numbers, the average of the first three is

    16 and that of the last three is 14. If the last number is 17, then find the first number?
    A 22 Correct Answer Incorrect Answer
    B 23 Correct Answer Incorrect Answer
    C 32 Correct Answer Incorrect Answer
    D 25 Correct Answer Incorrect Answer

    Solution

    Let the four numbers be a, b , c and d. (a + b + c)/3 = 16 (a + b + c) = 48 ----- (i) (b + c + d)/3 = 14 (b + c + d) = 42 ----- (ii) Given that last number is 17 i.e. , d = 17, now putting this value in (ii) (b + c +17) = 42 (b + c) = 42-17 (b + c) = 25 ----- (iii) Now, putting value of (iii) into (i), (a + b + c) = 48 a + 25 = 48 a = 48-25 = 23 therefore, the first number is 23.

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