求助：问一道小六数学题 谢谢各位

973800qaz

Isaac  had some red and blue marbles in a container . First ,he added in 22  red marbles and as result ,40% of the marbles in the container were blue . Next , he added in another 180 blue marbles and  as a result , 60% of the marbles were blue . Finally , he removed some red marbles such that the ratio of the remaining red marbles to the remaining blue marbles was 1:3.
(a)  How many red marbles did he have at first?
(b)   How many red marbles did he remove?

ivyguo

(A) 194
(B) 108

ivyguo

我用方程 R 是原来红的 B是原来蓝的(A)
4R+88=6B

6R+132=4B+720
10R=1940
R=194
B=144


(B)
194+22=216
144+170=324
324除3=108
216-108=108

973800qaz

谢谢，儿子看完了明白了怎样用方程解这道题，谢谢。

但是他还想知道不用方程还有其他的方法解这道题吗？

4justice

973800qaz

4justice 发表于 8-8-2013 23:18

谢谢你啦，看你很勤奋呢，这么晚了还爬上来答题。