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 16 km/h after every hour. He reached his destination in 18 hours. If his initial speed was 30 km/h, then what was his average speed in the whole journey?
    A 126 km/h Correct Answer Incorrect Answer
    B 136 km/h Correct Answer Incorrect Answer
    C 166 km/h Correct Answer Incorrect Answer
    D 146 km/h Correct Answer Incorrect Answer

    Solution

    Total distance travelled by A = (18/2) × {2 × 30 + (18 – 1) × 16} = 9 × (60 + 272) = 2988 km Required average speed = 2988/18 = 166 km/h

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