Sara and jo both ran an 8km race Sarah took 55 mins to run the whole race jo started the race 3 mins later than Sara but caught up when they

Question

Sara and jo both ran an 8km race Sarah took 55 mins to run the whole race jo started the race 3 mins later than Sara but caught up when they had both travelled 6 km of Sara and jo both ran at constant speed what is jos speed in 2dp

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Khánh Gia 5 years 2021-08-13T17:40:56+00:00 1 Answers 28 views 0

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  1. thuthuy
    0
    2021-08-13T17:42:31+00:00
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    Answer:

    9.41 km/h

    Step-by-step explanation:

    The total distance of the race, d = 8 km

    The time Sarah took to run the race, t = 55 mins

    The time Jo started the race = 3 mins later than Sara

    The point Jo caught up with Sarah = 6 km into the race

    The rate at which Jo and Sarah ran = Constant speed

    The required information = Jo’s speed

    From the information given, Sarah’s speed, v = 8 km/(55 mins) = (8/55) km/min × 60min/h = 96/11 km/h

    The time it would take Sarah to run 6 km = 6 km/(8 km/(55 mins)) = 41.25 mins

    Given that Jo started 3 minutes late, and they both arrive at 6 km into the race at the same point in time, the time it took Jo to arrive at 6 km into the race = The time it took Sarah – 3 minutes

    ∴ The time it took Jo to run the 6 km = 41.25 minutes – 3 minutes = 38.25 minutes

    Given that Jo ran at a constant speed, and speed = distance/time, we have;

    Jo’s speed = 6 km/(38.25 min) = 8/51 km/min × 60 min/h = (160/17) km/h ≈ 9.41 km/h.

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