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#1 2007-03-15 19:36:33

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

a welfare ......

A welfare association collected Rs.202500 as donation from residents of a colony.If each paid as  many rupees as there were many residents,find the number of residents.

how can we do this?????


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
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#2 2007-03-15 23:53:50

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

Re: a welfare ......

If you can write this information down as an equation, it becomes very simple.
x people each paid x rupees, and 202500 rupees were collected overall.

If you can write down an expression for the total rupees collected in terms of x, it will be very easy to solve.


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

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#3 2007-03-16 00:36:18

George,Y
Member
Registered: 2006-03-12
Posts: 1,379

Re: a welfare ......

N residents
each payed N rupee
Together N² rupee
N²=202500=250000-47500=250000-50000+2500=500²-2×500×50+50²=(500-50)²


X'(y-Xβ)=0

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#4 2007-03-16 00:41:11

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

Re: a welfare ......

how u got 47500


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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#5 2007-03-16 02:08:34

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

Re: a welfare ......

George is making it a bit more complicated than it needs to be.

Once you have that N² = 202500, you can just square root both sides and you're done.


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

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#6 2007-03-16 09:30:17

Stanley_Marsh
Member
Registered: 2006-12-13
Posts: 345

Re: a welfare ......

Nice Technique , George.~


Numbers are the essence of the Universe

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#7 2007-03-16 14:16:46

George,Y
Member
Registered: 2006-03-12
Posts: 1,379

Re: a welfare ......

By guessing 250000 (=500²). I have already (A±b)²=202500 in mind. 500 is the quickest candidate for A, in the same way 250000 for A².

The steps since 250000-47500 is just trying to get the square root of 202500 without a calculator at hand. It's only a trial solution, like the way we solve integration.

Last edited by George,Y (2007-03-16 14:21:21)


X'(y-Xβ)=0

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#8 2007-03-18 02:06:36

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

Re: a welfare ......

i suppose this somewhat related with square and square roots because this question was in squares chapter


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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#9 2007-04-03 01:17:41

soha
Real Member
Registered: 2006-07-07
Posts: 2,530

Re: a welfare ......

please help me in this , coz it has not gone in my head till now , and you all are explaining , but i am unablle to understand , so wHAT WILL I DO ?
its really very very very very confusing.


"Let us realize that: the privilege to work is a gift, the power to work is a blessing, the love of work is success!" smile smile
- David O. McKay

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#10 2007-04-03 01:32:56

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: a welfare ......

See mathsyperson’s explanation. Just take the square root of 202 500.

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