摘要： 解(1)设2007职业中专的在校生为x 万 人 根据题意得:1500×1.2x -1500x ＝600 ··························································· 3分 解得: ··············································· 5分 所以． ···························································································· 7分 答:略． ············································ 8分
网址：http://m.1010jiajiao.com/timu3_id_465793[举报]
现有60克含盐15%的盐水,问加入多少克的盐可使盐水浓度变为20%?
解:设加入x克的盐,根据题意,列出的方程是
[ ]
A. 60·15%+x=20%·(60+x) B. 15%·(60+x)=60·20%+x
C. 60·15%－x=20%·(60+x) D. 60·20%+x=15%·(60+x)
查看习题详情和答案>>