Puzzle

[WilliamD]

Can anyone work out the answer to this? Young niece has to submit answer tonight.

Lonnie is taking the train to the British Library in
London. He tells Rosti the hour of his train’s
departure and he tells Ann at which minute it
leaves. He also tells them both that the train
leaves between 0600 and 1000.
They consult the timetable and find the following
services between those times:
0632, 0643, 0650; 0717, 0746; 0819, 0832;
0917, 0919, 0950.
Rosti then says, ‘I don’t know when Lonnie’s
train leaves, but I’m sure that neither does Ann.’
Ann replies, ‘I didn’t know his train, but now I do.’
Rosti responds, ‘Now I do as well!’
When is Lonnie’s train and how do you know?

[Lisasbolt]

Have not got a clue, maybe the 3 glasses of white wine have not helped, leave Lonnie and tell him to get a taxi

[Martin H]

I think I got this.

Rosti knows the hour but knows that Ann doesn't know, so it must be an hour with no unique minutes.
It can't be 06 because that has 0643 and 43 is unique.
It can't be 07 because 46 is unique.
So the hour must be 08 or 09.

Once Ann has worked this out, if she knows the time it must be at minutes that aren't shared between 08 and 09. So it must be 08:32, 09:17 or 09:50.

Rosti now knows the exact time, so it must be 08:32.

Gold star please

[jackarmy]

Lonnie took the bus, trains dont call at the library

[SusieG]

OMG! I'm so thick, even though you've just explained it, still don't get it ...!!!!!
Was always a dunce at school all those decades ago when it came to figuring out this type of puzzle ...

[WilliamD]

Martin you are a clever man. Thank you. I shall pass this on to niecey, who I know will be chuffed.

[veggiechicken]

Martin aka Smarty pants! Here are the other puzzles to keep you busy http://www.ncl.ac.uk/maths/outreach/...uestions16.pdf

[Martin H]

Martin aka Smarty pants! Here are the other puzzles to keep you busy http://www.ncl.ac.uk/maths/outreach/...uestions16.pdf

Life's too short.

[lottie dolly]

OMG! I'm so thick, even though you've just explained it, still don't get it ...!!!!!
Was always a dunce at school all those decades ago when it came to figuring out this type of puzzle ...

Me neither,i suspect we are far from on our own be easier to find the way out a maze

[Lumpy]

So that's where the ex Lord Lucan went..............

[Jungle Jane]

When you google the question,there's a few links about maths challenge & this thread,lots of people will be able to see this answer? Should it be deleted do you think?

[molyyyy]

Help

I think I got this.

Rosti knows the hour but knows that Ann doesn't know, so it must be an hour with no unique minutes.
It can't be 06 because that has 0643 and 43 is unique.
It can't be 07 because 46 is unique.
So the hour must be 08 or 09.

Once Ann has worked this out, if she knows the time it must be at minutes that aren't shared between 08 and 09. So it must be 08:32, 09:17 or 09:50.

Rosti now knows the exact time, so it must be 08:32.

Gold star please

Hia just wondering why the unique numbers are eliminated and how rosti concludes that it is 8:32? thanks!

[veggiechicken]

Have you been set this puzzle too Molly

[molyyyy]

Have you been set this puzzle too Molly

yes ahahaha it's extremely hard!

[Martin H]

Hia just wondering why the unique numbers are eliminated and how rosti concludes that it is 8:32? thanks!

"Rosti then says, ‘I don’t know when Lonnie’s
train leaves, but I’m sure that neither does Ann.’"

Rosti know the hour. He can only be sure that Ann doesn't know unless all the minute numbers on his hour are not unique.

I'll let you work the rest out yourself by expanding on my previous explanation.