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13 replies to this topic

#1 Aatif

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Posted 18 February 2008 - 04:47 AM

You have bricks which are 20 cm tall and 10 cm wide (and 10 cm deep). You have to build a hedge which is 20 cm tall, and 1 m long. How many different patterns can you make keeping the minimum number of bricks in use? What is special in this number?
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#2 MysteryKidakaJohnDoe

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Posted 18 February 2008 - 09:53 AM

Spoiler for a guess

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#3 Aatif

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Posted 18 February 2008 - 09:58 AM

Spoiler for a guess

Nope!
89. Detailed solution would come later!
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#4 Aatif

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Posted 20 February 2008 - 09:43 AM

Seems long enough to keep the puzzle open! So here is the solution:
Spoiler for A stony treat

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#5 roolstar

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Posted 22 February 2008 - 09:57 AM

Interesting...

It feels like the Fibonacci Series but it will take too long to explain how.

So i'll stick to my intuition.

1 1 2 3 5 8 13 21 34 55 89

The 11th number in the sequence!
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#6 Aatif

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Posted 22 February 2008 - 10:08 AM

Interesting...

It feels like the Fibonacci Series but it will take too long to explain how.

So i'll stick to my intuition.

1 1 2 3 5 8 13 21 34 55 89

The 11th number in the sequence!

Yup .. the sequence is Fibonacci series but why did you choose 89 as ur answer?!
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#7 roolstar

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Posted 22 February 2008 - 11:27 AM

Yup .. the sequence is Fibonacci series but why did you choose 89 as ur answer?!

Well I simply started with the second 1 in the series with the first brick (1 possible answer)
The 2 bricks got me 2 easy...
3 got me 5 a little more complicated
so for 10 bricks 11th number not 10th!

This is because length = 2X width...
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#8 roolstar

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Posted 22 February 2008 - 01:55 PM

Now what if the bricks were 30x10x10??

How can we still use the same sequence? (if possible)

Of course we consider the wall to be 30x120 cm

Edited by roolstar, 22 February 2008 - 01:58 PM.

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#9 Aatif

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Posted 22 February 2008 - 05:11 PM

Now what if the bricks were 30x10x10??

How can we still use the same sequence? (if possible)

Of course we consider the wall to be 30x120 cm

Umm it would be an offshoot of another Fibonacci I think.
Spoiler for A higher hedge

The problem will become more interesting if I would say that you have to make a 40x150x10 wall using minimum number of 20x10x10 brick. What are the no. of patterns? What are the no. of patterns for general case of this?
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#10 Aatif

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Posted 22 February 2008 - 05:19 PM

Well I simply started with the second 1 in the series with the first brick (1 possible answer)
The 2 bricks got me 2 easy...
3 got me 5 a little more complicated
so for 10 bricks 11th number not 10th!

This is because length = 2X width...

Roolstar .. Actually 3 should have got you 3 only! 4 bricks would be needed t make 5 patterns .. but I figure, you got the point..
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