Question 482392
There are 4 members of a band, and they all walk at different rates. Only 2 people can cross the bridge at the same time, and the two peopl have to wal at the same sppeed of the slowest walker. Whoever goes across the bridge has to have a flashlight and so someone must always carry the flashlight. Here is how long it takes each person to cross the bridge. Tyler 1 minute, Beach 2 minutes, Grace 5 minutes and coleen 10 minutes.  you cannot cary another person or toss the flashlight back across the river. Can you find a way to get everyone across in no more than 17 minutes  if so explain if not explain.

<pre>
Let's nickname Tyler "#1"
Let's nickname Beach "#2"
Let's nickname Grace "#5"
Let's nickname Colleen" "#10".
Let's nickname the river "R"


We start with the 4 people and the river in this order

Order #1,#2,#3,#4,R

#1 and #2 go across which takes                2 minutes

Order is now #5,#10,R,#1,#2

#2 returns with the flashlight which takes     2 minutes

Order is now #2,#5,#10,R,#1

#5 and #10 go across, which takes             10 minutes

Order is now #2,R,#1,#5,#10

#1 returns with the flashlight which takes     1 minute

Order is now #1,#2,R,#5,#10

#1 and #2 go across, which takes               2 minutes

Order is now R,#1,#2,#5,#10
--------------------------------------------------------
Total time                                    17 minutes     

Edwin</pre>