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# How to set up the Double matrix for this ? I get confused

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VP
Joined: 30 Jun 2008
Posts: 1022
How to set up the Double matrix for this ? I get confused [#permalink]

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28 Sep 2008, 00:22
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

How to set up the Double matrix for this ? I get confused with which term to fill in which column.

Please see the problem and help me identify the terms which i should fill in the boxes A,B,X and Y.

Of 28 people in the park, 12 are Children and the rest are adults. 8 have to leave at 3 pm; rest do not. If after 3 pm, there are 6 children still in the park, how many adults are still in the park?
Attachments

Double Matrix.jpg [ 14.62 KiB | Viewed 1339 times ]

_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

SVP
Joined: 17 Jun 2008
Posts: 1507
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 03:18
I have tried in the attachment.
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temp1.pdf [6.6 KiB]

VP
Joined: 05 Jul 2008
Posts: 1379
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 12:11
amitdgr wrote:
How to set up the Double matrix for this ? I get confused with which term to fill in which column.

Please see the problem and help me identify the terms which i should fill in the boxes A,B,X and Y.

Of 28 people in the park, 12 are Children and the rest are adults. 8 have to leave at 3 pm; rest do not. If after 3 pm, there are 6 children still in the park, how many adults are still in the park?

I am big fan of the matrix. But I do not see any reason why we need to set up a matrix to solve this. I agree that matrix helps, but this problem was pretty straight forward.

That said, I always look for terms in such a way that one is the negation of the other. We need to find events X and !X. Here the point that some one is not a C is that some one is A. It probably is not as open in other problems which say eats lima beans and do not eat lima beans
Senior Manager
Joined: 04 Aug 2008
Posts: 370
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 16:09
hope this tactics can help:

1 first u fill for totals starting from grand total 28 in our case

2 then fill other two totals on the sides

3 then plug in the trigger and just to the operations to fill the blanks w numbers

I got 14
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Manager
Joined: 22 Sep 2008
Posts: 119
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 17:51
even i got 14 as answer.

child <= 3 pm = 6 ..(12-6=6).............eq1

child > 3 pm = 6 (given)

Adult <= 3 pm = 2 (6 +x= 8)

Adult > 3 pm = 14 (28-8 =20 , eq1)6+y =20 , so y = 14)

Thanks
Vishal Shah
VP
Joined: 30 Jun 2008
Posts: 1022
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 20:59
Thank you guys. The answer for the problem I posted above is 14.

Should we use the Double Matrix method with the following problem? Is there a better way of solving this problem?

There are 58 vehicles in a parking lot. 24 are trucks, 30 are cars, and the rest are vans. 20 Vehicles are red, 16 are blue, and the rest are green. if there are 12 red trucks in the parking lot, 5 blue trucks, 4 red cars, What is the largest possible number of blue cars in the parking lot?

Thanks
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Manager
Joined: 22 Sep 2008
Posts: 119
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 21:51
11 blue car and 15 green car

am i right?
Manager
Joined: 22 Sep 2008
Posts: 119
Re: MGMAT - OVERLAPPING SETS [#permalink]

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28 Sep 2008, 21:55
24 30 4
12 4 4 20 Red
5 11 0 16 Blue
7 15 0 22 Green

hope you are clear with breakup

Thanks
Vishal Shah
SVP
Joined: 17 Jun 2008
Posts: 1507
Re: MGMAT - OVERLAPPING SETS [#permalink]

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29 Sep 2008, 23:00
icandy wrote:
amitdgr wrote:
How to set up the Double matrix for this ? I get confused with which term to fill in which column.

Please see the problem and help me identify the terms which i should fill in the boxes A,B,X and Y.

Of 28 people in the park, 12 are Children and the rest are adults. 8 have to leave at 3 pm; rest do not. If after 3 pm, there are 6 children still in the park, how many adults are still in the park?

I am big fan of the matrix. But I do not see any reason why we need to set up a matrix to solve this. I agree that matrix helps, but this problem was pretty straight forward.

That said, I always look for terms in such a way that one is the negation of the other. We need to find events X and !X. Here the point that some one is not a C is that some one is A. It probably is not as open in other problems which say eats lima beans and do not eat lima beans

icandy, I agree. I think, I just tried with what amitdgr had posted in the question.
VP
Joined: 18 May 2008
Posts: 1207
Re: MGMAT - OVERLAPPING SETS [#permalink]

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30 Sep 2008, 00:32
This problem can be solved very easily using matrix method. I got answer as 11.Find the solution in attachment
amitdgr wrote:
Thank you guys. The answer for the problem I posted above is 14.

Should we use the Double Matrix method with the following problem? Is there a better way of solving this problem?

There are 58 vehicles in a parking lot. 24 are trucks, 30 are cars, and the rest are vans. 20 Vehicles are red, 16 are blue, and the rest are green. if there are 12 red trucks in the parking lot, 5 blue trucks, 4 red cars, What is the largest possible number of blue cars in the parking lot?

Thanks

Attachments

matrix.jpg [ 18.05 KiB | Viewed 1237 times ]

VP
Joined: 30 Jun 2008
Posts: 1022
Re: MGMAT - OVERLAPPING SETS [#permalink]

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30 Sep 2008, 04:20
ritula wrote:
This problem can be solved very easily using matrix method. I got answer as 11.Find the solution in attachment
amitdgr wrote:
Thank you guys. The answer for the problem I posted above is 14.

Should we use the Double Matrix method with the following problem? Is there a better way of solving this problem?

There are 58 vehicles in a parking lot. 24 are trucks, 30 are cars, and the rest are vans. 20 Vehicles are red, 16 are blue, and the rest are green. if there are 12 red trucks in the parking lot, 5 blue trucks, 4 red cars, What is the largest possible number of blue cars in the parking lot?

Thanks

_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Re: MGMAT - OVERLAPPING SETS   [#permalink] 30 Sep 2008, 04:20
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# How to set up the Double matrix for this ? I get confused

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