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发表于 9-8-2013 20:21:18|来自:新加坡
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原题 There were 138 more boys than girls in a Judo Club .When 3/4 of the boys and 2/3 of the girls graduated from the club,there were 80 children left .How many boys graduated from the club?
分析:
3/4 of the boys and 2/3 of the girls --> 所以boys一共分为4个单位,girls一共分为3个单位 --> 4B + 3G = Total
138 more boys than girls --> 4B - 3G = 138
When 3/4 of the boys and 2/3 of the girls graduated --> 1个单位的boys和一个单位的girls剩下 --> 1B + 1G = 80
解答:
4B - 3G = 138 -- (1)
1B + 1G = 80 -- (2)
3B + 3G = 240 -- (3)
(1) + (3) : 7B = 138 + 240
7B = 378
1B = 54
3B = 162
Ans: 162 boys graduated from the club.
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