SOLUTION: A man bought 7 pounds of coffee and 10 pounds of butter for a total of $58.50 . A day later, the prices had not changed and he bought 7 pounds of coffee and 5 pounds of butter

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Question 349191: A man bought 7 pounds of coffee and 10 pounds of butter for a total of $58.50 .
A day later, the prices had not changed and he bought 7 pounds of coffee and 5 pounds of butter for $39.75 .
Find the price per pound of the butter.

Answer by unlockmath(1688) About Me  (Show Source):
You can put this solution on YOUR website!
Hello,
Let's have x be the cost for coffee and y be the cost for butter. We can set up 2 equations from this:
7x+10y=58.5
7x+5y=39.75
Multiply the second equation by -2 to get:
-14x-10y= -79.5
Now add this to the first equation to get:
-7x=-21
Now divide both sides by -7 to get:
x=3
y=3.75
There we go--butter is $3.75 per pound.
Make sense?
RJ
www.math-unlock.com