Cross the river

3 men and 3 ghosts need to cross the river. There's a ferry which can only take 2 of them each time. No matter where they are, if ghosts appears more than human does, human will be ate by ghosts. How can you get all of them across the river?

Ghost #1 takes human #1 across river
(left: ghost #2 & #3, human #2 & #3) (boat: ghost #1)(right: human #1)

ghost #1 returns and takes ghost #2 across
(left: ghost #3, human #2 & #3)(boat:ghost #1) (right: human #1 and ghost #2)

ghost #1 returns again and takes human #2 across
(left: ghost #3, human #3) (boat: ghost #1) (right: human #1 & #2 and ghost #2)

ghost #1 returns again and takes ghost #2 across
(left: human #3)(boat: ghost #1) (right (human #1 & #2 and ghost #2 & #3)

ghost #1 returns again and takes human #3 across, both get off and join the group
(all 6 on other side)

I don't understand dormdough, lol maybe I'm tired, I will back tomorrow to read again

dormdough wrote:Ghost #1 takes human #1 across river
(left: ghost #2 & #3, human #2 & #3) (boat: ghost #1)(right: human #1)

ghost #1 returns and takes ghost #2 across
(left: ghost #3, human #2 & #3)(boat:ghost #1) (right: human #1 and ghost #2)

well, if ghost #1 returns, then there are 3 ghosts and 2 human on the left side, which means, human will be ate!
Wrong

Let me explain - the ghost #1 is staying in the boat.

Just because the boat carries two persons, doesn't mean two must disembark each time.

So, everyone starts on the left side of the river.
Ghost1 and human1 get in the boat.
They go across, human1 gets off, ghost1 stays on and rides across back to the left side - but stays on the boat.

So: now ghost2 and ghost3 are still on the left with human2 and human3, human1 is on the right, and ghost1 is still in the boat.
(left side: 2x ghost, 2x human)(right side: 1x human)(boat: 1x ghost)

Then, ghost2 joins ghost1 on the boat, they ride across, and only ghost2 gets off. Ghost1 rides back across, and again, stays on the boat.

So: Now ghost3 is remaining on the left, with human2 and human3. On the right side is ghost2 and human1. Still on the boat is ghost1.
(left side 1x ghost, 2x humans)(right side: 1x ghost, 1x human)(boat: 1x ghost)

Then, human2 joins ghost1 on the boat. They travel across, and human2 gets off. Ghost1 stays on the boat, and returns to the left, but again stays on the boat.

(left side is ghost #3 + human #3 (even), boat still has ghost #1, and right side has human#1 and human #2 + ghost #2 (safe))

Then, ghost1 (still in the boat) rides back to left side and ghost 3 gets on.
Ghost3 gets off on other side, ghost1 is still on the boat.
Now, we have (left side: only human#3)(boat ghost1, right side ghost2 and ghost3, and also human#1 and human#2)(even and safe)

Then, ghost1 (still chilling on the boat) rides back for human#3, they both ride across and get off.

All 6 have crossed.

Shall I draw a picture or diagram perhaps?

I understand what you're saying, but it's the wrong answer...
Anyways, if ghost #1 wants to pick up someone from the riverside, he has to pull over, which means it counts once he reach the side.

Aw shucks

Well - too bad. I shall try again on the next one!

(and I'll keep my answer shorter)

Cheers

I will post the correct answer on Monday, coz the Mega Blast, so I bet you guys won't have time for this LOL...

Step 1
Left Side: Ghost #2, Ghost #3, Human #2, Human #3
Boat: Ghost #1, Human #1
Right Side:
Action: Ghost #1 and Human #1 Go across, and Human #1 Drops off Ghost #1 And Returns.
Return Boat: Human #1
New Right Side: Ghost #1

Step 2
Left Side: Human #1, Human #2, Human #3
Boat: Ghost #2, Ghost #3
Right Side: Ghost #1
Action: Ghost #2 and Ghost #3 Go across, and Ghost #3 Drops off Ghost #2 And Returns.
Return Boat: Ghost #3
New Right Side: Ghost #1, Ghost #2

Step 3
Left Side: Human #3, Ghost #3
Boat: Human #1, Human #2
Right Side: Ghost #1, Ghost #2
Action: Human #1 and Human #2 Go Across, Human #1 drops off Human #3 and picks up Ghost #1.
Return Boat: Human #1, Ghost #1
New Right Side: Ghost #2, Human #3

Step 4
Left Side: Ghost #1, Ghost #3
Boat: Human #1, Human #3
Right Side: Ghost #2, Human #3
Action: Human #1 and Human #3 Go Across, Human #1 and Human #3 get off the boat and Ghost #2 returns.
Return Boat: Ghost #2
New Right Side: Human #1,2,3

Remaining Steps:
Ghosts go and pick up the ghosts taking one step to transport each at a time.

I will wait on Monday, I think

oh,This is my worst!

sorry,I do not know the answer!

LOL

Congrats, Fluffy! You got it!
But I think better give the others an explanation:

| | Destination

Step 1:
1 human and 1 ghost go across, 1 human return.
| | D -------- | | ---------- | |

Step 2:
2 ghosts go across, 1 ghost return.
| | ---------- | | ---------- | |

Step 3:
2 human go across, 1 ghost and 1 human return.
| | ---------- | | ---------- | |

Step 4:
2 human go across, 1 ghost return.
| | ---------- | | ---------- | |

Step 5:
2 ghosts go across, 1 ghost return.
| | ---------- | | ---------- | |

Step "6:
2 ghosts across, DONE!
| | ---------- | |

That was pretty complicated.

trose7 wrote:That was pretty complicated.

It is quite a complicated riddle

FluffyWolf2 wrote:

trose7 wrote:That was pretty complicated.

It is quite a complicated riddle

LOL, coz it's a riddle