New Enroll for RBI, PFRDA & NABARD Intro Class! April 18 at 9:15 PM

    Question

    Average of 8 numbers is 80. If average of first four and

    last two numbers is 70 and 60, respectively then find the fifth number given that ratio of fifth and sixth number is 7:5, respectively.
    A 140 Correct Answer Incorrect Answer
    B 130 Correct Answer Incorrect Answer
    C 120 Correct Answer Incorrect Answer
    D 125 Correct Answer Incorrect Answer

    Solution

    Let fifth and sixth numbers be ‘7x’ and ‘5x’, respectively. So, 7x + 5x = 80 × 8 – 70 × 7 – 60 × 5 = 240 Or, 12x = 240 Or, x = 20 So, fifth number = 20 × 7 = 140

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