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

    Question

    A was travelling from point X to point Y. He increased

    his speed by 10 km/h after every hour. He reached his destination in 14 hours. If his initial speed was 30 km/h, then what was his average speed in the whole journey?
    A 90 km/h Correct Answer Incorrect Answer
    B 85 km/h Correct Answer Incorrect Answer
    C 95 km/h Correct Answer Incorrect Answer
    D 75 km/h Correct Answer Incorrect Answer

    Solution

    Total distance travelled by A = (14/2) × {2 × 30 + (14 – 1) × 10} = 7 × (60 + 130) = 1330 km Required average speed = 1330/14 = 95 km/h

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