Brain Teasers

[anj]

Nice one, Mal. I may have the answer to The Appointment.

Twenty to ten, interpreted as 22:10

Highlight above to reveal my answer. (Another good idea, Mal)

[hadaso]

Here's a nice math riddle It might take a while to load. I spent a few hours on implementing in javascript but it's still an ugly job. If anyone's interested I'd be happy to see improvements. (For the curious people: there is no image on that page!)

[Malc 44]

There is a bus with 7 girls on board.
Each girl has 7 bags.
In each bag, there are 7 big cats
Each big cat has 7 little cats.
Each cat has 4 legs.

Question: How many legs are present in the bus?

[Malc 44]

A man wanted to get into his work building, but he had forgotten his code. However, he did remember five clues. These are what those clues were:

The fifth number plus the third number equals fourteen.

The fourth number is one more than the second number.

The first number is one less than twice the second number.

The second number plus the third number equals ten.

The sum of all five numbers is 30.

What were the five numbers and in what order?

[odedp]

Originally Posted by Malc 44

A man wanted to get into his work building, but he had forgotten his code. However, he did remember five clues. These are what those clues were:

The fifth number plus the third number equals fourteen.

The fourth number is one more than the second number.

The first number is one less than twice the second number.

The second number plus the third number equals ten.

The sum of all five numbers is 30.

What were the five numbers and in what order?

The numbers were: 74658

[Malc 44]

Originally Posted by odedp

The numbers were: 74658

Wow! that was quick odedp, well done. Although the guy deserves to be locked out if he could remember all of those clues but not the actual code!

Can you work out the previous cats teaser?

_Malc

[odedp]

Originally Posted by Malc 44

Can you work out the previous cats teaser?

_Malc

Maybe 10992?

[Malc 44]

Originally Posted by odedp

Maybe 10992?

Not the answer I was looking for, but maybe you included something that wasn't in the teaser?

[n5bb]

Originally Posted by Malc 44

There is a bus with 7 girls on board.
Each girl has 7 bags.
In each bag, there are 7 big cats
Each big cat has 7 little cats.
Each cat has 4 legs.

Question: How many legs are present in the bus?

Like many such puzzles, the answer depends on how you interpret the wording. Here are things I would question:

• Is a "girl" a human girl, a cat girl, or another species?
• Does each girl have 2 legs? They might not. Or should we assume that there are 7 human girls, each with 2 legs, for a total of 14 human legs on the bus?
• We are told that 7 girls are on board the bus. But we are not so explicitly told that the bags, big cats, or little cats are on the bus. Should we assume this? I think that the solution rides on what you assume with regard to who is on the bus.

Bill

[CyberSmurf]

Originally Posted by Malc 44

Not the answer I was looking for, but maybe you included something that wasn't in the teaser?

Maybe odedp was including the bus driver?.

[CyberSmurf]

Originally Posted by n5bb

Like many such puzzles, the answer depends on how you interpret the wording. ...

I was wondering if the puzzle twists on sombodys definition of the word "present".
Like someone, not me, might say the cats aren't present because they are in the bags.

[odedp]

Originally Posted by CyberSmurf

Maybe odedp was including the bus driver?.

He definitely was

[n5bb]

But the bus might be parked with no driver. Or the driver might be using hand controls and have no legs (although that would be a dangerous bus ride if there was a crash). Or there might be 5,000 spiders on the bus, and we should count their legs. Or the girls might have bags, but the bags are back in their houses.

These puzzles usually hinge on some issue about giving you too much or not enough information, and what is explicitly specified and what we assume.

Bill

[Malc 44]

Originally Posted by n5bb

But the bus might be parked with no driver. Or the driver might be using hand controls and have no legs (although that would be a dangerous bus ride if there was a crash). Or there might be 5,000 spiders on the bus, and we should count their legs. Or the girls might have bags, but the bags are back in their houses.

These puzzles usually hinge on some issue about giving you too much or not enough information, and what is explicitly specified and what we assume.

Bill

Ha ha! Bill, you're clearly reading too much into this teaser! but you certainly made me laugh. Yes, odedp included the bus driver assuming that there must be one present, but I think we can assume that as he wasn't mentioned, he cannot be counted. So the answer to the teaser is????

_Malc

[n5bb]

Only the cats are mentioned as having legs. But they are not mentioned as being specifically on board. So if you only go by what was stated (with no assumptions), there are no legs on board. Since the number of legs on each cat was specifically listed but was not listed for the girls, you can't assume the girls have legs and you can't assume a driver with legs is on board. Each girl "has" a bag, but there is no mention of the girls holding or otherwise placing the bags on board. For example, you could have said "each girl has a Hummer SUV", but there is no reason to assume that the Hummer is on board. The English word "has" presents quite a bit of ambiguity.

There is a bus with 7 girls on board.
Each girl has 7 bags.
In each bag, there are 7 big cats
Each big cat has 7 little cats.
Each cat has 4 legs.

If I assume things that aren't specified, then I can get a wide range of answers. For example, here is one scenario if I assume no driver (only the specified girls, big cats, and little cats on board), 2 legs for each girl, 4 legs for each big or little cat, and both girls and all cats included on board):

• There are 7 girls on board, and each has 2 legs, for a total of 7 x 2 =14 girl legs on board.
• Each girl has 7 bags on board with them, for a total of 7 x 7 = 49 bags on board.
• In each bag there are 7 big cats (each with 4 big cat legs), so there are 7 x 4 = 28 big cat legs per bag.
• Since there are 49 bags on board, there are 49 x 28 = 1372 big cat legs on board.
• For each big cat, there are 7 little cats (each with 4 little cat legs), so there are 7 x 4 = 28 little cat legs per big cat.
• Since there are 7 big cats per bag, there are 7 x 28 = 196 little cat legs per bag. Since there are 49 bags on board, there are 49 x 196 = 9604 little cat legs on board. Note that this is exactly 7 times the number of big cat legs, since there are 7 little cats for each big cat.
• So the total number legs on board the bus is the sum:

   14 girl legs
 1372 big cat legs
 9604 little cat legs
______________________________________________
10990 total legs (including girl, big cat, and little cat legs)

Bill