An optimization problem that elementary school students can also solve - find the minimum time to cross the bridge
Adam, Steve, Greg and John want to cross an ancient bridge at night. For safety reasons, they decided to go beyond two people at a time. However, they only have one flashlight, because everyone who crosses the bridge needs lights, so they can only cross the bridge at the speed of the slower of the two. If Adam, Steve, Greg and John cross the bridge each is 2 minutes; 28 minutes; 20 minutes; and 1.5 minutes, then what is the shortest time for all four people to cross the bridge?
Solution: This question implies two restrictions. Two people must cross the bridge, and one person must send the flashlight back.
method is as follows:
First, Adam and John crossed the bridge first, and they took 2 minutes, and then John returned with the
flashlight, and added another 1.5 minutes. At this time, John stayed at the bridge head, and then Steve and Greg crossed the bridge for 28 minutes, and handed the flashlight to Adam, he went back for 2 minutes, and finally Adam and John crossed the bridge again
for another 2 minutes, and a total of 2+1.5+28+2+2=35.5 minutes.
