把3升果汁倒入400毫升的杯子里，至少要倒多少次． equation:x=8 8 (50%/0.625+(2(1/3)-1(1/5))*(3/7))/4(1/6)． equation:x=(50%/0.625+(2(1/3)-1(1/5))*(3/7))/4(1/6) (54/175) 一堂课40分钟，学生实验用了(1/5)小时，老师讲解用了(1/4)小时，其余的时间学生做作业