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

    Question

    A train covers a certain distance at a speed of 24 km/h

    and the next same distance with a speed of 30 km/h and the next same distance with a speed of 40 km/h. find the average speed?
    A 12.6 km/hr Correct Answer Incorrect Answer
    B 30 km/hr Correct Answer Incorrect Answer
    C 45 km/hr Correct Answer Incorrect Answer
    D 37.8 km/hr Correct Answer Incorrect Answer
    E 18.9 km/hr Correct Answer Incorrect Answer

    Solution

    Since the distance is same in all the conditions. Therefore, Average speed = 3xyz/(xy + yz + zx) Average speed = 3 x 24 x 30 x 40/(24 x 30 + 30 x 40 + 40 x 24) Average speed = 3 x 24 x 30 x 40/(720 + 1200 + 960) = 86400/2880 = 30 km/hr

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