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Esther D Leonelli

Posts: 391
Registered: 12/4/04
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Posted: Nov 18, 2005 3:22 PM
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Date: Thu, 17 Nov 2005 16:56:13 -0600
From: "Martha Haehl" <Martha.Haehl@mcckc.edu>
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Subject: Re:
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You described my dilemma in trying to solve the problem and get a numerical answer. It seems you have to make assumptions of some sort that may be implied but are not explicitly stated.

Martha

The egg problem:
Due to a 30% increase in the price of eggs, 3 less eggs are available for £7.80. Is the present rate of eggs per dozen:
a) £8.64
b) £9.36
c) £8.88 or
d) £10.40? and how did you get that?

It really depends on how you read the problem and the assumptions you make. If you assume that the 7.80 is both the price of eggs previous to the increase and also of the eggs minus 3 after the increase, then Ed Wall's solution makes sense. --B. 9.36
This is a reasonable reading of the problem but not the only way to look at it. It also contradicts the common sense notion that eggs are sold by the dozen, but it is more mathematically pure because one shouldn't assume anything not specifically written in the problem, (although it does assume the same price of 7.80 which I do not think is evident in the writing of the problem.)

But if you read it as I did, making the assumption that the eggs both previously and currently were sold by the dozen (since the question asks about price per dozen) and that the 7.80 is the new price of a dozen eggs less 3, (and the old price is an unknown,) you then can figure the new price per egg as 7.80/9 and multiply the result by 12 to get the new price per dozen: D. 10.40 in which the 30% increase is unnecessary information.

However if you truly leave out both assumptions, your new price per egg times the new number of eggs would equal 7.80, looking like this in equation form:

[(1.3)P/E][E-3]=7.80

where P= old price of the eggs and E = the original number of eggs at the old price.

But I think this leaves the problem insoluble as there is not enough information given, unless you return to assuming either A. Eggs are only sold by the dozen--both previous to and after the increase in price, or B. 7.80 is both the price of eggs previous to the increase and also of the eggs minus 3 after the increase.

Are there any holes in my reasoning?

Don Lauser



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Subject: eggs situation need help!!
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due to a 30% increase in the price of eggs, 3 less eggs are available for £7.80.is the present rate of eggs per dozen is:
a) £8.64
b) £9.36
c) £8.88 or
d) £10.40? and how did you get that?

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Martha Haehl
816-759-4221
martha.haehl@mcckc.edu
Metropolitan Community College-Penn Valley
3201 S.W. Trafficway
Kansas City, MO 64111

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