数学问题，大家讨论•••

欢迎好运 · 发表于 6-6-2011 00:18:12|来自：新加坡

我是好运的女儿，我有一道题目要请大家帮忙，因为答案与提供的答案有些出入,所以请大家指教，问题如上.

sweetcandytian · 发表于 12-6-2011 22:56:35|来自：新加坡

This is P6 problem sums, the last question:
There are more pupils in School A than School B. 30% of the pupils in School A is 45 more than 40% of the pupils in School B. If 10% of the pupils in School A leaves to join School B, there will be 200 more pupils in School A than School B.
a) How many pupils are there in School B?
b) How many percent less pupils are there in School B then School A? Leave your answer as fraction in the simplest form.

sweetcandytian · 发表于 13-6-2011 16:25:42|来自：新加坡

sweetcandytian · 发表于 13-6-2011 16:42:45|来自：新加坡

d

露营 · 发表于 14-6-2011 13:19:17|来自：新加坡

我是“露营”的女儿，你的这条题目我好像做出来了，但不保证是对的,错了不找我哦。:P
3/10 of A -45=4/10 of B
10/10-1/10=9/10
9/10=200=10/10 of B+1/10 of A
45乘以3=135
9/10-135=12/10 of B
200-135=65
2/10 of B-1/10 of A=65
4/10 of B-2/10 of A=65乘以2
                           =130
1/10 of A=130+45
            =175
175乘以3-45=480
480除以4乘以10=1200
175乘以10=1750
1750-1200=550
550/1750=11/35
                                                                     Ans:a)1200
                                                                           b)11/35
你有答案吗？是对是错请告诉我。

欢迎好运 · 发表于 15-6-2011 00:07:22|来自：新加坡

回复露营的帖子

我跟你作法稍微不同，但答案相同。应该没错。

写得一大堆，要回复却不可以，显示内部错误，无法显示。。。。。。

欢迎好运 · 发表于 15-6-2011 00:19:44|来自：新加坡

1)  0.3A-0.4B=45
2)  (1-0.1)A-200=B+0.1A
   0.8A-200=B
0.3A-0.4(0.8A-200)=45
                  0.02A=35
                        A=1750
B=1750*0.8 - 200=1200

(1750-1200)/1750=11/35

答案:1)1200 2)11/35

shima · 发表于 17-6-2011 11:01:47|来自：新加坡

回复静雯的帖子

请教一道数学题：
如下：

Sava had some money. After spending $10 on 3 writing pads and 7 pencils, he would be short of $0.40 if he were to buy 1 more writing pad. If he were to buy 1 more pencil, he would have $0.60 left.
A) How much did each writing pad cost?
B) How much did Siva have at first?

多谢！