作者Jamesco (詹姆士抠)
看板GMAT
标题Re: [计量] P1~DS
时间Sat Sep 5 07:21:27 2009
※ 引述《a2515125 (Bobshih)》之铭言：
: How many hours did it take Helen to drive from her house to her parents' house?
: (1) Helen's average speed on this trip was 72 kilometers per hour.
: (2) If Helen's average speed on this trip had been 8 kilometers per hour greater, it would have taken her 1 hour less.
: 答案是C
: 请问如何列式？1+2
设总距离为X;需要的时间为Y
X/72=Y
X/80=Y-1
解联立方程式求Y即可....
--
▁ ▁ ▁ ◢ █████ http://www.wretch.cc/blog/hippojimmy
▏ ▏ ▏ ◢█ █ ◢██◣ █◢◣◢◣ ◢██◣ ◢██◣
████████ █ █ █ █ █ █ █ █
████████ ◣ █ ◢███ █ █ █ ████ ◥██◣
◥█ █ █ █ █ █ █ █ █ █
★喇叭詹★ ◥ ◥██◤ ◥███ █ █ █ ◥██◤ ◥██◤ ㊣
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 98.194.0.158