[eye30]

Your task, (if you wish to accept it, little bit of MI) is to measure 45 minutes.


At yor disposal are two cords and matches to light the cords.

1. The two cords are twisted from various materials and so their different segments can burn at different rates.

2. Each cord burns from end to end in exactly one hour.

[AlanHo]

Don't peek before you really really need to.....

(click to show/hide)

Take one cord and light both ends (this doubles the rate at which it shortens)

Light one end of the other cord at the same time.

After 30 minutes the first cord will burn out - the second cord will by then have burned half way

Light the other end of the second cord which will now take only 15 minutes to burn out.

Hence the overall time will be 45 minutes.

[Shambles]

Not an answer, but I like the way you've targeted the thread at bumpkin

Brian tickler #10

[eye30]

Not an answer, but I like the way you've targeted the thread at bumpkin

Brian tickler #10

 

[eye30]

Don't peek before you really really need to.....

(click to show/hide)

Take one cord and light both ends (this doubles the rate at which it shortens)

Light one end of the other cord at the same time.

After 30 minutes the first cord will burn out - the second cord will by then have burned half way

Light the other end of the second cord which will now take only 15 minutes to burn out.

Hence the overall time will be 45 minutes.

I had a peek just to see if my answer agreed to yours....

Top man Alan. Another correct answer....

ps.
I'm sorry I didn't know Alan some 50 odd years ago as I could have posted my homework questions on here and Alan have provided the answers with no effort from me

Now for the next Alan tickler...

[AlanHo]

I do have a slight advantage - most of the puzzles you have posted, or very similar ones,  have been published in the UK weekly MENSA tests.

Hence I may not know the answer straight away - but it stirs my brain (or is it Brian) into following a previously trod path.

[eye30]

I do have a slight advantage - most of the puzzles you have posted, or very similar ones,  have been published in the UK weekly MENSA tests.

Hence I may not know the answer straight away - but it stirs my brain (or is it Brian) into following a previously trod path.

 

[ibrokeit]

I really should look into joining MENSA - keep on getting told I have a smart arse, smart mouth, etc. - hmmm... maybe it isn't I have but rather I am