# 2 ladies and 2 girls need to cross a river in a boat big enough for 1 lady or 2 girls. How do they do it?

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2 ladies and 2 girls need to cross a river in a boat big enough for 1 lady or 2 girls. How do they do it?
posted Oct 30, 2017

+1 vote
1. 2 girls take the boat to the other side and 1 comes back.
2. A lady takes the boat to the other side and a girl on that side brings the boat back
3. The girls yet again bring the boat back to the other side and 1 of them comes back.
4. The other lady goes to the other side and the girl on that side brings the boat back and takes the other girl on 1st side back to the other side.
All have crossed by now.

To simply let us denote the entities involved as follows;

Let,

Girls be called as G
Boat be called as B

Let W be the west coast where everyone is currently present and
E be the east coast where everyone should be at the end.

Step 1:
Let the 2 girls cross from W to E
W [L,L]
E[G,G,B]

Step 2:
Let G return with the boat
W [L,L,G,B]
E[G]

Step 3:
Let L go with B
W [L,G]
E[L,G,B]

Step 4:
Let G return with the boat
W [L,G,G,B]
E[L]

Step 5:
Let the 2 girls cross from W to E
W [L]
E[L,G,G,B]

Step 6:
Let G return with the boat
W [L,G,B]
E[L,G]

Step7:
Let L go with B
W [G]
E[L,L,G,B]

Step 8:
Let G return with the boat
W [G,G,B]
E[L,L]

Step 9:
Let the two girls go in the boat to E
W [empty]
E[L,L,G,G,B]

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These are the conditions that have to be followed.

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+1 vote

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