75.ds: S and M respectively drived t hours, S covered 350 miles and M covered 325 miles, what is M's speed?
(1)t=5
(2)S's speed is 5 mile/hour greater than M's
评价:选D,条件1->M'speed=325/t=325/5=65miles/hour, 条件2->350/t-325/t=5->t=5,所以M'speed=325/t=325/5=65miles/hour
如此题,难道还有算出1,2各自结果,在看是否结果一样,否则算是矛盾吗?
我现在好糊涂,以前从没有注意到此累问题,请帮忙看看! |