Question

    A truck driver has to cover a total distance of 260 km

    in 4 hours. He drives at a speed of 56 km/h for the first 75 minutes, and the next 90 km at speed of 60 km/h. At what speed (in km/h) must he drive the remaining distance in order to complete the journey in 4 hours?
    A 65 Correct Answer Incorrect Answer
    B 58 Correct Answer Incorrect Answer
    C 80 Correct Answer Incorrect Answer
    D 75 Correct Answer Incorrect Answer

    Solution

    Distance covered in the first 75 minutes = 56 × 1.25 = 70km Time taken to complete the 90km stretch = (90 ÷ 60) = 1.5 hours Remaining distance = (260 - 70 - 90) = 100km Remaining time = (4 - 1.25 - 1.5) = 1.25 hours Hence, he must drive at = 100 ÷ 1.25 = 80 kmph

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