New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A is cycling at an average speed of 48 km/hr such that

    he can reach a certain point at 12 noon. If he cycles at 80 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 50 km/hr Correct Answer Incorrect Answer
    B 55 km/hr Correct Answer Incorrect Answer
    C 60 km/hr Correct Answer Incorrect Answer
    D 56 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 48 km/hr = (x/48) hours Time taken when speed is 80 km/hr = (x/80) hours According to the question, (x/48) – (x/80) = 2 Or, 5x – 3x = 2 × 240 Or, x = 240 km Time taken to travel 240 km with speed of 48 km/hr = 240/48 = 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 = 240/4 = 60 km/hr

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