中1的3條文字數學題!

1)There are 2 sizes of boxes,large box and small box.The large box contain 48

chocolates while the small box can contain 30 chocolates.Now,we have 306

chocolates.Find the number of large boxes and small boxes needed to contain

all the chocolates.(The boxes should have no empty spaces after containing

the chocolates.)

2)Peter bought 72 pencil boxes.However,the receipt has been lost accidentally.He

can remember the total cost of the 72 pencil boxes is X679.Y dollars(X and Y are

the digits that he forget).Find the value of X and Y .Hence,find the selling price of

each pencil box.

3)There is a beaker of 900g sugar solution which contain 6% of pure sugar.To

increase its concentration of sugar to 10%,how many grams of water should be

evaporated?

更新:

1)有大小兩種盒,大盒可裝48粒巧克力,小盒可裝30粒.現在要裝306粒巧克力,要用大,小盒各幾個才沒有浪費?(各盒均需裝滿巧克力,沒有剩餘空間)

2)彼得買了72個筆盒.可是,他遺失了購物的賬單.他只記得72個筆盒總值是X679.Y元(X及Y是他忘記了的數字).求X及Y的值.由此,求每個筆盒的售價.

1 個解答

評分
  • 8 年前
    最愛解答

    1. Let there are b large boxes and s small boxes, so

    48b + 30s = 308

    8b + 5s = 51 ... (dividing both sides by 6)

    As 16 + 35 = 51

    therefore b = 2, s = 7. That is,

    There are 2 large boxes and 7 small boxes.

    2. As 72 = 8*9, so 79Y must be divisible by 8, ie. Y = 2.

    And X6792 must be divisible by 9, so X = 3.

    That is X = 3, Y = 2, the price of each pencil box is :

    3679.2 / 72

    = $ 51.1

    3. There are 900*6% pure sugar, ie. 54g pure sugar.

    In order to make the concentration to 10%, the solution must have only 540g.

    900 - 540 = 360

    So, 360g of water should be evaporated.

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