Marco and me have been solving riddles for fun this afternoon. Here is one:

And another one:

This is a classic. I really love it. It has a long description, but stick with me because it's worth it.

There are 4 people who need to cross a narrow bridge at night with only one torch.

The four people each have different travelling times:

Person 1 crosses in 1 minute
Person 2 crosses in 2 minutes
Person 1 crosses in 5 minutes
Person 1 crosses in 10 minutes

Only two people can cross at a time and one person has to come back over the bridge to give the torch to the others still waiting to cross.

While crossing, you have to use the slowest time of the two people because they have to walk the same pace.

You have to add the person who comes back to your total time.

They need to cross in 17 minutes. How?

Here's an example:

5 and 10 go over (that's 10 minutes) and then 5 comes back with the torch (that's a total of 15 minutes). Then 5 and 2 go over (that's 20 minutes---and you're already over the time limit . . . )

How can you get all four people to the other side in 17 minutes?

Note that there is a logical answer. It won't be anything like "they can throw the torch to the other side instead of walking it over", or "they can all wait till sunrise", or "why don't they jog over and increase their times", etc!

Try them, it is really good fun. Don't Google it. We didn't


William said...

Ok ive got the first one on the link. lol

number 2 - im assuming uve got these person numbers wrong yeah?

so u send 1 and 2 across first.

--- 1 minetes total so far ---

then one returns.

--- 3 minetes total so far ---

then send 5 and 10 across

--- 13 minetes total so far ---

u send 2 back across with the touch

--- 15 minetes so far ---

1 and 2 then cross

--- everones over... 17 minetes ---

William said...


--- 1 minetes total so far ---

should be

--- 2 minetes total so far ---

Kelvin Watson said...
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