Question

两个杯中分别装有浓度为40%与10%的食盐水,倒在一起混合成食盐水的浓度为30%;

Answer 1

设：40%的食盐水质量为m,10%的食盐水质量为n .根据题意有计算式：(1).(m*40% + n*10%) /(m+n)=30%0.40m+0.10n=0.30m+0.30nn=0.50m .(2).(m*40%+0.50m*10%+300g*20%)/(m+0.50m+300g)=25%0.40m+0.05m+60g=1.50m*0.25+7...