请教一道数学题，

After taking the Metro to Dupont Circle in Washington, DC, Jess reached

street level by walking up the escalator at a brisk rate, taking 54 steps during

the trip to the top. Suddenly curious about the length of the escalator,

Jess returned to the bottom and walked up the same escalator at

a leisurely rate, taking steps two thirds as often as on the

first trip, taking 40 steps in all. How many steps can

be seen on the visible part of the escalator?

所有跟帖： 

• Not so sure, but should be ... -slowguy- ♂ (16 bytes) () 04/24/2012 postreply 20:36:49

• 回复：Not so sure, but should be ... -xyz- ♀ (82 bytes) () 04/24/2012 postreply 20:54:24

• Sorry for lacking of details ... -Slowguy- ♂ (558 bytes) () 04/24/2012 postreply 21:06:02

• Thank you very much! -xyz- ♀ (0 bytes) () 04/25/2012 postreply 08:03:05

• 用解方程可以吗? -yddad- ♂ (516 bytes) () 04/24/2012 postreply 22:22:22

• Thank you very much! -xyz- ♀ (0 bytes) () 04/25/2012 postreply 08:02:27

• 回复：请教一道数学题， -李卓静- ♀ (358 bytes) () 04/25/2012 postreply 18:28:37

• 答案是2吗？ -李卓静- ♀ (358 bytes) () 04/25/2012 postreply 18:29:44

• 刚次答案2 好像算错了，应该是14 -李卓静- ♀ (196 bytes) () 04/25/2012 postreply 18:49:11

• 刚次答案2 好像算错了，应该是14 -李卓静- ♀ (196 bytes) () 04/25/2012 postreply 18:49:14

• Wow. 新加坡的数学教材和习题册 may be necessary for you, but ... -slowguy- ♂ (36 bytes) () 04/28/2012 postreply 19:28:11