Maths Riddles

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Maths Riddles

Postby mathtuition88 » Tue Aug 20, 2013 2:40 pm

Maths can be fun too!
Build up interest in Mathematics by trying out some of these interesting Maths Riddles.

1) Missing dollar riddle

Three guests check into a hotel room. The clerk says the bill is $30, so each guest pays $10. Later the clerk realizes the bill should only be $25. To rectify this, he gives the bellhop $5 to return to the guests. On the way to the room, the bellhop realizes that he cannot divide the money equally. As the guests didn't know the total of the revised bill, the bellhop decides to just give each guest $1 and keep $2 for himself. Each guest got $1 back: so now each guest only paid $9; bringing the total paid to $27. The bellhop has $2. And $27 + $2 = $29 so, if the guests originally handed over $30, what happened to the remaining $1?

Try it out before checking out the solution at http://en.wikipedia.org/wiki/Missing_dollar_riddle
Discussions and additions to this thread are warmly welcomed!

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Re: Maths Riddles

Postby atrecord » Tue Aug 20, 2013 4:11 pm

mathtuition88 wrote:Maths can be fun too!
Build up interest in Mathematics by trying out some of these interesting Maths Riddles.

1) Missing dollar riddle

Three guests check into a hotel room. The clerk says the bill is $30, so each guest pays $10. Later the clerk realizes the bill should only be $25. To rectify this, he gives the bellhop $5 to return to the guests. On the way to the room, the bellhop realizes that he cannot divide the money equally. As the guests didn't know the total of the revised bill, the bellhop decides to just give each guest $1 and keep $2 for himself. Each guest got $1 back: so now each guest only paid $9; bringing the total paid to $27. The bellhop has $2. And $27 + $2 = $29 so, if the guests originally handed over $30, what happened to the remaining $1?

Try it out before checking out the solution at http://en.wikipedia.org/wiki/Missing_dollar_riddle
Discussions and additions to this thread are warmly welcomed!




I remember this to be an age-old question. First came across this (or a similar one but perhaps background different) one probably about 35 yr ago when I was in pri sch...

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Re: Maths Riddles

Postby CloudeeDaz » Tue Aug 20, 2013 5:52 pm

Was also puzzled by the missing $1 when i read it earlier in the afternoon.
Now it suddenly becomes crystal clear... they paid $27, got back $3, total is $30. The $2 that the staff kept comes from the $27 .

The thing with me is, ask me again in a few weeks time and i will again go why huh? :? :rotflmao:

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Re: Maths Riddles

Postby CloudeeDaz » Wed Aug 21, 2013 11:00 am

:smile:
The Monty Hall Problem


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Re: Maths Riddles

Postby mathtuition88 » Wed Aug 21, 2013 2:08 pm

CloudeeDaz wrote::smile:
The Monty Hall Problem


I really like the Monty Hall Problem too, it is interesting and surprising!

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Re: Maths Riddles

Postby mathtuition88 » Wed Aug 21, 2013 2:13 pm

Source: http://betterexplained.com/articles/und ... y-paradox/

Understanding the Birthday Paradox

23 people. In a room of just 23 people there’s a 50-50 chance of two people having the same birthday. In a room of 75 there’s a 99.9% chance of two people matching.
True or false?

It sounds too amazing to be true (since there are 365 days a year), but it really is!

Visit http://betterexplained.com/articles/und ... y-paradox/ to see the reasoning behind it.

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