OG13 DS 90题

laoqian000

Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2.

我选C。但是，OG答案选E，很粗暴地简单解释(1)和(2)合起来不sufficient。。。
可是，明明 d1/r1=(d2+30)/(r2+30)>d2/r2
那不就sufficient了吗？！

求大神解释

laoqian000

HermanLu 发表于 2014-8-22 11:35
d1/r1=(d2+30)/(r2+30)>d2/r2 是建立在r2>d2的基础上也就是说(d2+30)/(r2+30)未必大于d2/r2  ...

感谢！！我刚刚想起了~还有可能等于。。。

HermanLu

d1/r1=(d2+30)/(r2+30)>d2/r2 是建立在r2>d2的基础上也就是说(d2+30)/(r2+30)未必大于d2/r2