SOLUTION: A farmer has two types of feed. One has 5% digestible protein and the other 15% digestible protein. How much of each type will she need to mix 100lb of 12% digestible protein feed?

Question 1042980: A farmer has two types of feed. One has 5% digestible protein and the other 15% digestible protein. How much of each type will she need to mix 100lb of 12% digestible protein feed?
Let 5% digestible protein = x lb
Let 15% digestible protein = y lb
Total feed = 100 lb
So, the first equation:

But, my problem is, how do I get the second equation?
Answer by ikleyn(52803) (Show Source): You can put this solution on YOUR website!
.
A farmer has two types of feed. One has 5% digestible protein and the other 15% digestible protein. How much of each type will she need to mix 100lb of 12% digestible protein feed?
Let 5% digestible protein = x lb
Let 15% digestible protein = y lb
Total feed = 100 lb
So, the first equation:

But, my problem is, how do I get the second equation?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The second equation is

0.05x + 0.15y = 0.12*100.

There is a bunch of lessons on mixture problems in this site that teach you on how to solve them
    - Mixture problems
    - More Mixture problems
    - Solving typical word problems on mixtures for solutions
    - Word problems on mixtures for antifreeze solutions
    - Word problems on mixtures for dry substances like coffee beans, nuts, cashew and peanuts
    - Word problems on mixtures for dry substances like candies, dried fruits
    - Word problems on mixtures for dry substances like soil and sand
    - Word problems on mixtures for alloys
    - Typical word problems on mixtures from the archive

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Comment from student: Thank you for the second equation! I have re-read the question for like a hundred times,
but I was still unable to figure out the second equation. Thank you again, but I'm still confused.
I mean, why do the 0.12 need to be multiplied with 100? Ah, I got it! I read the links to the lessons provided by you,
and it helps me a tonne! Thanks, I'll bookmark it.
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My response: I am glad to see/to hear it.

One more notice: You have your free of charge online textbook in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK
full of useful lesson, well structured and logically organized.

You also have the other free of charge online textbook in this site
    - GEOMETRY - YOUR ONLINE TEXTBOOK
with the same features . . .

You also have MEGA-TONNES other my lessons in this site on Pre-Algebra and Algebra-II.

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