New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

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

    16 and that of the last three is 15. If the last number is 21 then the first number is:
    A 22 Correct Answer Incorrect Answer
    B 21 Correct Answer Incorrect Answer
    C 24 Correct Answer Incorrect Answer
    D 28 Correct Answer Incorrect Answer

    Solution

    The last 3 numbers total =  3 × 15 = 45 So the middle 2 numbers will add to 45 – 21 = 24 First 3 numbers total = 3 × 48 = 48 So the first number is 48 – 24 = 24 ∴ The first number is 24

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