Problem: A boy was sent for $1.20 worth of eggs. On his way home he broke five eggs and thereby he paid twenty-four cents more per dozen of eggs. How many eggs did he buy?
How would one go about setting up this problem?
How would one go about setting up this problem?
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n = number of eggs
x = price of 1 egg
n*x = 1.20 ==> x=1.20/n -- (1)
note that if each dozen eggs cost 24c more, each eggs cost 2 cents more (0.02$)
1.20 /(n-5) = 0.02+x
==> 1.20 = (n-5)*(0.02+x) -- (2)
replacing (1) in (2), you get:
1.20 = (n-5)*(0.02+1.20/n)
1.20 = 0.02n + 1.20 - 0.1 - 6/n
0 = 0.02n -0.1 - 6/n
If you multiply by 50n to simplify:
0 = n^2 - 50n - 300
solve with: http://www.ajdesigner.com/phpquadraticequation/quadraticequation.php
positive root: 20 eggs!
so you had 20 eggs at 6c each...
since you broke 5, you ended up with 15 eggs...1.20/15 = 0.08... 8c, 2c more!
x = price of 1 egg
n*x = 1.20 ==> x=1.20/n -- (1)
note that if each dozen eggs cost 24c more, each eggs cost 2 cents more (0.02$)
1.20 /(n-5) = 0.02+x
==> 1.20 = (n-5)*(0.02+x) -- (2)
replacing (1) in (2), you get:
1.20 = (n-5)*(0.02+1.20/n)
1.20 = 0.02n + 1.20 - 0.1 - 6/n
0 = 0.02n -0.1 - 6/n
If you multiply by 50n to simplify:
0 = n^2 - 50n - 300
solve with: http://www.ajdesigner.com/phpquadraticequation/quadraticequation.php
positive root: 20 eggs!
so you had 20 eggs at 6c each...
since you broke 5, you ended up with 15 eggs...1.20/15 = 0.08... 8c, 2c more!
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