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#101 2005-08-22 22:40:32

mathsyperson
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Registered: 2005-06-22
Posts: 4,900

Re: Problems and Solutions


Why did the vector cross the road?
It wanted to be normal.

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#102 2005-08-22 23:07:47

justlookingforthemoment
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Registered: 2005-05-26
Posts: 2,161

Re: Problems and Solutions

And 'Ganesh's Puzzles' doesn't have a subtitle anymore.

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#103 2005-08-22 23:49:49

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,612

Re: Problems and Solutions

LOL, mathsy! I put the "z" there when I was trying to get them to work ... to tell you the truth, in all the confusion, I kinda' lost count, and given that this is a 44 magnum, the most powerful handgun in the world, ... sorry, where was I?


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#104 2005-08-23 21:04:41

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Problem #k+1
In a University, a student has to take necessarily Physics, Chemistry or Mathematics. The students are permitted take any two of them or even all the three of them. If 85 students take Physics, 65 students take Chemistry, 100 students take mathematics, 30 students take both Physics and Chemistry, 40 students take both Physics and Mathematics and none of the students take Chemistry and Mathematics or all three of them, how many students are there in the University?


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#105 2005-08-23 22:56:28

wcy
Member
Registered: 2005-08-04
Posts: 117

Re: Problems and Solutions

this could be done by drawing a Venn diagram, i suppose

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#106 2005-08-24 16:34:02

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Problem #k+2

I have a certain number of eggs in my store.
If you divide the number of eggs by 2 there will be one egg left.
If you divide the number of eggs by 3 there will be two eggs left.
If you divide the number of eggs by 4 there will be three eggs left.
If you divide the number of eggs by 5 there will be four eggs left.
If you divide the number of eggs by 6 there will be five eggs left.
If you divide the number of eggs by 7 there will be six eggs left.
If you divide the number of eggs by 8 there will be seven eggs left.
If you divide the number of eggs by 9 there will be eight eggs left.
If you divide the number of eggs by 10 there will be nine eggs left.

If you divide the Number of eggs by 11 there will be NO EGGS left!
What is the minimum number of eggs I can have in my store?


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#107 2005-08-25 20:26:53

ganesh
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Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Problem #k+3

A cube of dimensions 10cm x 10cm x 10cm is made up of smaller cubes of dimensions 1cm x 1cm x 1cm. If the outermost layer of smaller cubes are taken off, how many smaller cubes would be left?


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#108 2005-08-26 18:39:59

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Problem #k+4

A polyhedron has 12 faces(sides) and 18 edges. How many vertices does it have?


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#109 2005-08-27 02:08:51

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

Re: Problems and Solutions

Last edited by kylekatarn (2005-08-27 02:10:54)

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#110 2005-08-27 02:14:06

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

Re: Problems and Solutions

the post got really strange...

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#111 2005-08-27 11:34:15

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,612

Re: Problems and Solutions

It does look odd - that is my "hide" tag misbehaving. Job for me, hey?


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#112 2005-08-27 22:10:23

wcy
Member
Registered: 2005-08-04
Posts: 117

Re: Problems and Solutions

what happened to the old problems before the forum got hacked?

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#113 2005-08-28 06:54:39

Roraborealis
Member
Registered: 2005-03-17
Posts: 1,594

Re: Problems and Solutions

The ones in the Puzzles and Games board?


School is practice for the future. Practice makes perfect. But - nobody's perfect, so why practice?

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#114 2005-08-29 20:03:52

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Solution to problem#k+3 : kylekatarn is correct.

Problem # k+5

Use each digit 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 exactly once to form two five-digit numbers that when multiplied produce the largest quantity.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#115 2005-08-29 20:54:45

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,612

Re: Problems and Solutions

You mean like this:  97531×86420 = 8428629020  ?

Can anyone do better?


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#116 2005-08-29 23:28:17

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Thats what I thought of immediately on seeing the problem!
I am not saying you're correct, I'm not saying you're wrong....
I leave the problem open for some days smile


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#117 2005-08-30 18:01:22

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Problem # k+6

A woman and her grandson have the same birthday. For six consecutive birthdays, she is an integral multiple of his age. How old is the grandmother at the sixth of these birthdays?

(This was true for me and my maternal grandmother, although we didn't have the same birthday. For most of 6 consecutive years, her age was an integral multiple of mine) smile


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#118 2005-08-30 20:06:41

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

Problem # k+7

Mike and Jim attempted to solve a quadratic equation. Mike
made a mistake in writing down the constant term. He ended up with the
roots (4, 3). Jim made a mistake in writing down the coefficient of x. He
got the roots as (3, 2). What are the roots of the original quadratic equation?


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#119 2005-08-31 00:43:15

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

Re: Problems and Solutions

this is my solution

Last edited by kylekatarn (2005-08-31 00:54:01)

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#120 2005-08-31 00:55:01

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

Re: Problems and Solutions

mathisfun, is it possible to implement the [img]tag inside the [hide]tag?? It would be very usefull...

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#121 2005-08-31 09:44:09

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,612

Re: Problems and Solutions

I know I have to sit down and make that [hide]tage work properly ... maybe I will get a chance in the next few days.

Nice work on the solution kylekatarn, that was some silly mistake they made! (BTW b'=-5 I think)


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#122 2005-08-31 10:09:31

kylekatarn
Member
Registered: 2005-07-24
Posts: 445

Re: Problems and Solutions

MathsIsFun wrote:

I know I have to sit down and make that [hide]tage work properly ... maybe I will get a chance in the next few days.

Nice work on the solution kylekatarn, that was some silly mistake they made! (BTW b'=-5 I think)

Thank you mathisfun. b' is indeed -5!! silly me:)

I uploaded the GIF with corrected solution.
Thanks again.

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#123 2005-08-31 10:47:03

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,612

Re: Problems and Solutions

Didn't affect the result, I only noticed it because I was trying to understand how you solved it!


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#124 2005-08-31 16:19:31

ganesh
Moderator
Registered: 2005-06-28
Posts: 20,915

Re: Problems and Solutions

The solution to problem # k + 7 given by kylekatarn is correct.
The sum of the roots is 7 and their product is 6.

Problem # k+8

In a number system the product of 44 and 11 is 2124. The
number 3111 of this system, when converted to the decimal number system, becomes____________.


It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi. 

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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#125 2005-08-31 19:39:11

wcy
Member
Registered: 2005-08-04
Posts: 117

Re: Problems and Solutions

my answer is

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