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What is the maximum number of pieces that a circular pie can

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marcodonzelli
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What is the maximum number of pieces that a circular pie can [#permalink] New post   Updated on: 14 Nov 2013, 12:53
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E

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30% (01:23) correct 70% (01:15) wrong based on 595 sessions
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What is the maximum number of pieces that a circular pie can be divided into by four linear cuts?

A. 6
B. 8
C. 9
D. 10
E. 11
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E

Originally posted by marcodonzelli on 15 Mar 2008, 11:52.
Last edited by Bunuel on 14 Nov 2013, 12:53, edited 1 time in total.
Added the OA.
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Re: What is the maximum number of pieces that a circular pie can [#permalink] New post   25 Feb 2012, 03:59
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marcodonzelli wrote:
What is the maximum number of pieces that a circular pie can be divided into by four linear cuts?

A. 6
B. 8
C. 9
D. 10
E. 11

Can someone show this to me with a picture?


Such kind of combinations problems are always about a pattern recognition.

Maximum pieces:
0 line gives 1 whole piece;
1 line will gives 2 pieces: 1+1=2;
2 lines will give 4 pieces: 2+2=4;
3 lines will give 7 pieces: 4+3=7;
4 lines will give 7+4=11 pieces.

Similarly:
5 lines will give 11+5=16 pieces;
6 lines will give 16+6=22 pieces;
7 lines will give 22+7=29 pieces.

So, generally kth line will add k new pieces.

Answer: E.

P.S. Though I agree, it doesn't seem to be GMAT type of question.
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Re: m19-22 [#permalink] New post   30 May 2008, 03:39
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It is more tasteful :wink:
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sreehari
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Re: logic [#permalink] New post   15 Mar 2008, 12:14
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Getting 11

Below is the picture
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Re: logic [#permalink] New post   16 Mar 2008, 01:43
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1. 1st line can divide a circular pie by maximum 2 pieces
2. 2nd line gives us maximum 4 pieces
3. 3rd line can cross 3 pieces (to cross 4 piece is impossible) and we obtain 1+3*2=7 pieces
4. 4th line can cross maximum 4 pieces and we obtain 3+4*2=11

It can be solve less than 1min by means of the consecutive steps
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Re: logic [#permalink] New post   16 Mar 2008, 08:24
marcodonzelli wrote:
sreehari wrote:
Getting 11

Below is the picture


how did you come up with this in 2 minutes?


Look to maximize the intersections for each line, shouldn't take long.
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Re: logic [#permalink] New post   19 Mar 2008, 01:53
the key of this problem is the next line must be intersect all the previous line.so the answer is 2+2+3+4=11.Paint a chart is a directly and simply method.
sorry ,my english is so poor and I can't clearly express my viewpoint.
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Re: m19-22 [#permalink] New post   30 May 2008, 03:17
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9 is the best I can do.
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Re: m19-22 [#permalink] New post   30 May 2008, 03:24
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11.

1 line: 2*1=1
2 lines: 2*2=4
3 lines: 4+3=7
4 lines: 7+4=11
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Re: m19-22 [#permalink] New post   30 May 2008, 03:32
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EUREKA !!!!! - although I dont know how to do it mathematically .... walker any explanations ??
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Re: m19-22 [#permalink] New post   30 May 2008, 03:40
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bsd_lover wrote:
EUREKA !!!!! - although I dont know how to do it mathematically .... walker any explanations ??


I guess it is better to go step by step, from 1 line to 4 lines
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Re: m19-22 [#permalink] New post   30 May 2008, 03:41
walker the big piece is for u - when u nail 750 ....
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Re: m19-22 [#permalink] New post   30 May 2008, 03:42
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bsd_lover wrote:
walker the big piece is for u - when u nail 750 ....


Agree, and I will cut it by 10000 pieces for all GMATclubbers who help me :)
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Re: m19-22 [#permalink] New post   30 May 2008, 03:43
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walker wrote:
11.

1 line: 2*1=2
2 lines: 2*2=4
3 lines: 4+3=7
4 lines: 7+4=11



typo walker,

for those who were perplexed by walker's method,

he is saying for \(P_n = P_{n-1} + n\)
which in plain english mean, every new line n will will create n new pieces
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Re: m19-22 [#permalink] New post   30 May 2008, 03:56
Wow, Wow, beautiful cake! Walker!

I follow the 50-50 rule, so I cut the cake maximum 8 peices. Now I understand how the rule 20-80 works! :o :o Thanks every body!

If I see this question in real Gmat, I must bring with me a cake! :lol:
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Re: m19-22 [#permalink] New post   30 May 2008, 03:58
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If I see this in real gmat I'll never eat a cake again ...
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Re: m19-22 [#permalink] New post   30 May 2008, 20:52
bsd_lover wrote:
If I see this in real gmat I'll never eat a cake again ...


hahahaha.. that's really funny. In my case, I'll be only focused on food after that point and not the quants. GMAT will be creaming me with such a question as my brain would immediately start thinking about food..
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Re: Maximum number of pieces [#permalink] New post   22 May 2010, 16:15
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Hope this helps !
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Re: What is the maximum number of pieces that a circular pie can [#permalink] New post   25 Feb 2012, 03:23
I personally don't like this question because it resembles too much of those brainteasers and I ended up with 14 pieces... 3 cuts would equal 7 pieces and then one linear straight slice horizontally would give me 14 pieces...
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Re: What is the maximum number of pieces that a circular pie can [#permalink] New post   17 Nov 2012, 02:22
Hii Bunuel.
Can you please explain the pattern. Though I understood the pattern, I am not able to visualize the pattern.
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Re: What is the maximum number of pieces that a circular pie can [#permalink]
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