匿名使用者
匿名使用者 發問時間: 教育與參考中小學教育 · 9 年前

急!!!英數題...please~

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John left his home at 8:00 a.m. He went southwest to buy breakest at a supermarket 5away from his home. Afterwards, he turned 90 degrees and walked 12 km to school in the southeast direction. he arrived at school at 8:50 a.m.

a. On his way to school, what was John's walking speed?

b. What direction is the school from John 's home?

c. After school, how long will it take John to go back home?

1 個解答

評分
  • 匿名使用者
    9 年前
    最佳解答

    a. 20.4km/h (or 20.400000000000000000000000000008)

    5km + 12km = 17km

    Total time - 50minutes (or 0.83333333333333333 hours)

    17 ÷ 0.83333333333333333 = 20.4

    b. Southeast

    c. 0.62hrs / 37.2mins

    [a² + b² =c²] c = school ⇔ home

    5² + 12² = c²

    15 + 144 = c²

    159 = c²

    12.6km = c

    Time = Distance ÷ Speed

    12.6 ÷ 20.4 ≈ 0.62hrs / 37.2mins

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