解:设哥哥骑车过x分钟追上弟弟根据题意得310x=60(10×2+x)解得x=4.8答:略
80X10X2÷(310-60)=1600÷250=6.4分钟
(60*20)/(310-60)=4.8分钟解:设哥哥骑车过x分钟追上弟弟根据题意得310x=60(10×2+x)解得x=4.8
哥哥走:160X2 = 320(米)走:80-60 = 20(米每分钟)时间:320/20 = 16(分钟)距离:60X16 + 160 = 1120