F.2 Mathematics (Ratio)

2013-01-26 11:38 pm
The are 24 pens in a pencil box.
The number of blue ball pens is 4 more than that of black ball pens.
The number of black pans is twice the number of pencils.

Find the ratio of the number of blue ball pens to the number of black ball pens to the
number of pencils

Please help!
Thank you very much!!!^^

回答 (3)

2013-01-27 3:42 am
✔ 最佳答案
Letn be the number of pencils.

The number of black ball pensis twice the number of pencils.
Then, the number of black ball pens = 2n

The number of blue ball pens is 4 more than thatof black ball pens.
Then, the number of blue ball pens = 2n + 4

There are 24 pens in a pencil box.
n + 2n + (2n + 4) = 24
5n + 4 = 24
5n = 20
n = 4

(Number of blue ball pens) : (Numberof black ball pens) :(Number of pencils)
= (2n + 4) : 2n : n
= (2 x 4 + 4) : (2 x 4) : 4
= 12 : 8 : 4
= 3 : 2 : 1
參考: 土扁
2013-01-31 7:40 am
一睇就知 001 個答案錯咗。

全部有 24 枝筆,若果數目比例係 8 : 2 : 1,即係全部筆嘅數目唔係整數,點會啱?
2013-01-26 11:46 pm
Let a be the number of black ball pens.
4a is the number of blue pens
1/2a is the number of pencil

the ratio of the number of blue ball pens to the number of black ball pens to the
number of pencils
=4a:a:1/2a
=8a:2a:a
=8:2:1


收錄日期: 2021-04-13 19:16:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130126000051KK00186

檢視 Wayback Machine 備份