Question

    A is cycling at an average speed of 24 km/hr such that

    he can reach a certain point at 12 noon. If he cycles at 36 km/hr, then he will reach the destination at 10 a.m. At what speed he should cycle to reach the destination at 11 a.m.
    A 28.8 km/hr Correct Answer Incorrect Answer
    B 23.8 km/hr Correct Answer Incorrect Answer
    C 22.8 km/hr Correct Answer Incorrect Answer
    D 25.8 km/hr Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let the distance to be travelled be ‘x’ km Time taken when speed is 24 km/hr = (x/24) hours Time taken when speed is 36 km/hr = (x/36) hours According to the question, (x/24) – (x/36) = 2 Or, 3x – 2x = 2 × 72 Or, x = 144 km Time taken to travel 144 km with speed of 24 km/hr = 144/24 = 6 hours Therefore, he started at 12 – 6 = 6 a.m. Therefore, required speed to reach the destination at 11 a.m. or 4 hours = 144/5 = 28.8 km/hr

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