题目
A man is thinking about travelling in China by bike.His front tyre(前胎) and back tyre(后胎) can ex
A man is thinking about travelling in China by bike.His front tyre(前胎) and back tyre(后胎) can exchange(互换).If a new tyre is used for the front wheel(前轮)，it runs 3000 km at most(至多).If it is used for the back wheel(后轮)，it runs 2000km at most.If he uses two new tyres,his bike runs ___________km at most.
A man is thinking about travelling in China by bike.His front tyre(前胎) and back tyre(后胎) can exchange(互换).If a new tyre is used for the front wheel(前轮)，it runs 3000 km at most(至多).If it is used for the back wheel(后轮)，it runs 2000km at most.If he uses two new tyres,his bike runs ___________km at most.
提问时间：2020-07-26
答案
x+(2000-x)*3/2=(3000-x)*2/3+x(要走最远2轮要同时耗尽,x代表轮子1作为后轮时行驶的路程)
解得：x=1200
sum=1200+（2000-1200）*3/2=2400
2400
解得：x=1200
sum=1200+（2000-1200）*3/2=2400
2400
举一反三
已知函数f（x）=x，g（x）=alnx，a∈R．若曲线y=f（x）与曲线y=g（x）相交，且在交点处有相同的切线，求a的值和该切线方程．
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
奥巴马演讲不用看稿子.为什么中国领导演讲要看?
想找英语初三上学期的首字母填空练习……
英语翻译
最新试题
热门考点