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

    Question

    A cyclist rides at a constant speed of 12 miles per hour

    for the first half of a journey. For the second half, the cyclist increases the speed to 18 miles per hour. What is the average speed for the entire journey?
    A 10.4 miles/hour Correct Answer Incorrect Answer
    B 14.4 miles/hour Correct Answer Incorrect Answer
    C 18.4 miles/hour Correct Answer Incorrect Answer
    D 24.4 miles/hour Correct Answer Incorrect Answer

    Solution

    ATQ, Let the total distance be 2x miles. Time taken for the first half = x/12 hours Time taken for the second half = x/18 hours Total time = x/12 + x/18 = 5x/36 hours Average speed = (2x) / (5x/36) = 72/5 = 14.4 miles per hour

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