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Percentage Increase in Cost of Eggs

Date: 8/4/96 at 21:2:21
From: Anonymous
Subject: Percentage Increase in Egg Cost

By what percent did the price of eggs increase from 1940 to 1950 if in 
1940 the eggs cost 17 cents and in 1950 the eggs cost 39 cents??

I have no clue as to what steps you would take to solve this problem.  
Could you help me?

Thanks so much :)

Date: 8/4/96 at 21:51:29
From: Doctor Paul
Subject: Re: Percentage Increase in Egg Cost

Well let's use common sense to estimate.  You should know that if the 
price doubles that's a 100 percent increase.  So if it went from 17 to 
34 it would be 100 percent.  So, by common sense, we can guess the 
answer will be about 110 percent.

Let's continue:

Here's the formula for finding percent increase:

starting price * x = finishing price

solve for x:
subtract 1 from x, multiply that number by 100 and that's your percent

let's do it!

17*x = 39
x = 39/17
x = 2.29412
x-1 = 1.29412
multiply by 100:

129.412 percent

So our original estimate was off by a little, but was still fairly 
close. You should learn the value of estimating!  It turns out to be 
very useful.

I hope this answers your question.  Feel free to send Dr. Math any 
more of your math questions.

Doctor Paul,  The Math Forum Check out our web site!   
Associated Topics:
Middle School Algebra
Middle School Fractions
Middle School Ratio and Proportion

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