Question

    The average number of novels on historical, thriller and

    fantasy in a library is 200, and the average number of novels on historical and fantasy is 190. If the number novels on fantasy is 15% less than the number of novels on thriller, then what is the number of novels on historical in the library?
    A 183 Correct Answer Incorrect Answer
    B 163 Correct Answer Incorrect Answer
    C 153 Correct Answer Incorrect Answer
    D 193 Correct Answer Incorrect Answer
    E 173 Correct Answer Incorrect Answer

    Solution

    Let the number of novels on historical, thriller and fantasy be x, y and z respectively. Given, (x + y + z)/3 = 200 => x + y + z = 600 ….. (1) And, (x + z)/2 = 190 => x + z = 380 ….. (2) From equation 1 and 2 Number of novels on thriller = y = 220 Number of novels on fantasy = 0.85 × 220 = 187 Therefore, number of novels on historical = 600 – (220 + 187) = 193

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