12.題我網路上有找到原文
A power boat and a raft both left dock A on a river and headed downstream.
The raft drifted at the speed of the river current. The power boat maintained
a constant speed with respect to the river. The power boat reached dock B
downriver, then immediately turned and traveled back upriver. It eventually
met the raft on the river 9 hours after leaving dock A. How many hours did it
take the power raft to go from A to B?
(A) 3 (B) 3.5 (C) 4 (D) 4.5 (E) 5
其他題目可至
http://www.artofproblemsolving.com/Wiki/index.php/2011_AMC_12A
(台灣看起來是考AMC 12A)
還有AMC12第22題 印象中AMC10也考了一模一樣的題目(因學生有問)
