0_o" asked in 教育與參考考試 · 2 decades ago

數學題~英文的....急需

有三題.....急需

1. Last week Milos spend 88 dollars to buy a number of shirts on sale for 8 dollars each and several pairs of jeans at 16 dollars each. If the same number of shirts and twice the number of jeans were bought, there would have been 13 items. Find the number of pairs of jeans bought and the number of shirts bought.

2. Norma moved from Ontario to Northern Alberta. In Toronto she kept a 50% antifreeze solution in her car which protected her car to -37度C. She had to increase the strength to 70% to give her car protection to -64度C. How much pure antifreeze should be added to 15 L of a 50% solution to obtain a 70% solution?

3. When Ban drove the 420 km from Toronto to Ottawa, he averaged 70 km/h. During the trip he drove 2 hours on icy roads and 4 hours on dry roads. Assuming that he drove at a steady rate in each case, how fast did he travel on each type of road surface?

就這樣~幫我寫一下過程(算式),如果有解釋,幫我用英文解一下

Update:

抱歉喔~我在把題目的instruction打上來~

Analyse each of the following problems. If it contains sufficient information and nothing extraneous,then solve it. If it contains extraneous information, then discard the extra facts and solve it. If it contains insufficient information,then label it indeterminate.

2 Answers

Rating
  • 2 decades ago
    Favorite Answer

    第一題無解

    第二題10L

    第三題無數個答

    請詳察題目是否有錯

    我再幫你解

    2005-11-09 15:57:48 補充:

    1. Assume shirts nos.=x ; jeans nos.=y

    8x+16y=88 & x+2y=13 ; since the later will be derived to 8x+16y=104 compare with the former 88=104, it's impossible, so there is no solution to this Question.

    2. Assume he need x liters of pure solution

    then (15。50%+x)/(15+x)=70% ; we can get x=10 liters

    3. Assume seepd on icy road is x km/hr & y km/hr on dry road

    2x + 4y=420 ; x+2y=210; since the information is insufficient, that we can have infinite sets of (x,y) answer matches with this question.

    ☆★☆★☆★☆★在這裡☆★☆★☆★

    (x,y)=(100,55),(110,50),(120,45),(130,40),...

    2005-11-09 15:59:58 補充:

    不知道這樣可以嗎?

    2005-11-09 16:14:46 補充:

    88≠104矛盾故無解

    x=11,y=0如果你把它代入第二式,就會發現8=13矛盾

    2005-11-09 16:17:49 補充:

    第三題實際上只提供一個條件,二元一次方程式有無限組解,在平面幾何上是一條直線

  • 2 decades ago

    抱歉喔~我在把題目的instruction打上來~

    Analyse each of the following problems. If it contains sufficient information and nothing extraneous,then solve it. If it contains extraneous information, then discard the extra facts and solve it. If it contains insufficient information,then label it indeterminate.

    2005-11-09 15:35:15 補充:

    第2題可以列一下算式嗎?

    2005-11-09 16:05:52 補充:

    關於第一題

    不會式88等於104吧,應該是8x等於88吧~所以x等於11吧

    2005-11-09 16:12:22 補充:

    其他的都行啊

    可是不會有無解的吧

    2005-11-09 16:12:58 補充:

    那第3題答案勒?

    2005-11-09 16:36:58 補充:

    那可以舉一個嗎(你說的無線組解)

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