求幾題數學題既答案!!!(10點!!)

[匿名]

2008-08-19 3:51 am

所有問題都要列式答哦!!~~thx^^

1. solve 7(y - 1) - 5(2 - y) = 3

2.Yoyo gets some 29-dollar notes.It is known that he has $360 and the number of 20-dollar notes is greater than that of 50-dollar notes by 4.Find the number of 20-dollar notes.

3. Kitty used 八分之三 of her poctet money to visit pandas in a Sichuan zoo.
It is known that ￥75 remained.How much pocket money did she have?

4.When Vinceent visited the Great Wall og China,he said,''The average height of the Great Wall plus 1.2 m should be six times of my height.''If Vinvent's height is 1.5 m,find the average height of the Great Wall.

5. There are three ink bottles and eight pens.The weight of an ink bottle is 4 times that of a pen.If an of the items are 1000 g is weight,how heavy is an ink
bottle?

回答 (1)

Uncle Michael

2008-08-19 7:46 am

✔ 最佳答案

1.
7(y - 1) - 5(2 - y) = 3
7y - 7 - 10 + 5y = 3
12y - 17 = 3
12y = 20
3y = 5
y = 5/3

======
2.
Let p be the number of 20-dollar notes.
Let q be the number of 50-dollar notes.

20p + 50q = 360 ...... (1)
p - q = 4 ...... (2)

(2) x 50:
50p - 50q = 200 ...... (3)

(1) + (3):
70p = 560
p = 8

Ans: Number of 20-dollar notes = 8

======
3.
Let ￥m be the pocket money of Kitty.

m - (3/8)m = 75
8m - 3m = 600
5m = 600
m = 120

Ans: Pocket money that she had = ￥120

======
4.
Let h m be the average height of the Great Wall.

h + 1.2 = 6 x 1.5
h + 1.2 = 9
h = 7.8

Ans: The average height of the Great Wall = 7.8 m

======
5.
Let w g be the weight of an ink bottle.
Then the weight of a pen = (w/4) g

3w + 8(w/4) = 1000
5w = 1000
w = 200

Ans: The weight of an ink bottle = 200 g
=

👍 0 👎 0