4 people cross a river - Solution
First the two women cross the river together (10 min). Then the quick woman (5) returns (+5=15).
Now the two men cross the river (+25=40). The other woman (10) returns with the boat (+10=50).
Now both women take their last journey to be re-united with their men … (+10=60).
YES ! You made it, they have crossed the river !
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im hot
atleast mention in question that how many people can travel together in question
First, the women cross the river which mean 10 minutes and then the 5-minutes babe stays on the other side (which mean 10+10=20 minutes)
The men cross the river (25 minutes, total 45 minutes) then the 5 minutes babe return with the boat (45+5 =50 minutes)
Then the last both women travel (50+10=60 minutes)
tada
So, is there any reason why they all have to ride ‘in’ the boat? I think the ladies can sit in the boat and row, while their slow men can hang on the outside of the back of the boat. Since its only a ~10 minute ride (not accounting for the drag created), they won’t suffer much. It’s sad that the men take longer to row than the women, so it serves them right.
There is another way:
1) 5 min woman and 10 min woman cross=5min
2) 5 min women returns=5min
3) 20 min guy + 25 min guy= 20min
4) 25 min guy returns=25min
5) 5 min woman and 25 min guy return=5min
Total: 60min
I don’t think the question is well defined. I saw this puzzle before so I know the answer. We can see the confusion in Jack’s answer, his 5th step would take 25 minutes, not 5, and you are 20 minutes over. I would expand the description as follows (for example):
every person is has to row and because of the drag created by their weights, the time needed for the boat to cross the river is the longer time of the two persons sitting in the boat.
The solution is not unique, as it does not matter which woman returns with the boat for the man.
Solution(s):
1) women cross the river = 10 minutes
2) 5min ((10min)) woman returns = 15min ((20min))
3) men cross = 40min ((45min))
4) 10min ((5 min)) woman returns = 50min ((=50min))
5) women cross again = 60 min
M.
I got another answer which also adds up to 60 mins:
-fast girl takes slow girl and leaves her at the end(5).
-fast girl goes back(5)
-fast man takes fast girl(20) and gets out at the end.
-fast girl back(5)
-slow man takes fast girl and they both get out at end(25)