Date: 5 Jun 1995 22:01:46 -0400 From: Angela Subject: Birdseed Formula Someone has 3 dollars and wants to buy two kinds of bird seed (one is $1.49/lb. and the other is $2.88/lb.) with it (and does not have the extra change for 6% tax). What is the formula for figuring out how much of each seed she can get?
Date: 6 Jun 1995 10:54:52 -0400 From: Dr. Ken Subject: Birdseed Formula Hello there! I think the first thing I'd do in this problem is convert each of the two prices to what they'll amount to after you tack on the tax. Since it's 6%, the two prices will be 1.06*1.49 = $1.58/lb and 1.06*2.88 = $3.05/lb. Then assuming she wants to spend her whole wad of 3 dollars, the amount of money she spends on one kind plus the amount of money she spends on the other kind should be a total of 3 dollars. That gives us the following equation, where x and y are the two kinds of seed: x*1.58 + y*3.05 = 3 The way you'd use this equation is like this: if you know you want 1/2 pound of the first kind of birdseed (ie. x=1/2), you plug that in and get .79 + y*3.05 = 3 y*3.05 = 2.21 y = .725 pounds of the second kind. Thanks for the question! -K
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