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    Question

    Determine the distance covered by the dog in 2 hours and

    30 minutes if the dog's speed is 15 km/h faster than the cow's. The time it takes for the cow to cover 210 km is 3 hours less than the time it takes for the dog to cover 450 km.
    A 150 km Correct Answer Incorrect Answer
    B 665 km Correct Answer Incorrect Answer
    C 250 km Correct Answer Incorrect Answer
    D 320 km Correct Answer Incorrect Answer
    E can't be determinded Correct Answer Incorrect Answer

    Solution

    We can say that the speed of cow is ‘a’ km/h Speed of dog = (a + 15) km/h According to question; 450/(a + 15) – 210/a = 3 150/(a + 15) – 70/a = 1 150x – 70(a + 15) = a(a + 15) 150a – 70a – 1050 = a2 + 15a a2 – 65a + 1050 = 0 Solving above equation we get a = 35, 30 So, speed of bus will be either 50 km/h or 45 km/h So distance cannot be determined

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