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 40 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 20 km/hr Correct Answer Incorrect Answer
    B 35 km/hr Correct Answer Incorrect Answer
    C 32 km/hr Correct Answer Incorrect Answer
    D 30 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 40 km/hr = (x/40) hours According to the question, (x/24) – (x/40) = 2 Or, 5x – 3x = 2 × 120 Or, 2x = 240 km Or, x = 120 km Time taken to travel 120 km with speed of 24 km/hr = 120/24 = 5 hours Therefore, he started at 12 – 5 = 7 a.m. Therefore, required speed to reach the destination at 11 a.m. or 4 hours = 120/4 = 30 km/hr

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