Question 87916:  Okay, I am taking an online Math class and have come across all of the types of work problems, Mystery #s, Money, Mixture & Motion problems. I am so stuck on this Mixture Problem. :
 
Ms. Post wants to mix 2 kinds of cereal. Type A sells at $2.20/lb and Type B sells at $4.20/lb. How many lbs of Type A should she use if she wants a 20 lb mixture selling at $3.00/lb.?
 
Well, I tried using problems in my lesson as an example for the chart.  
This is what I came up with and am pretty sure I got it wrong... 
2.20x+4.20(20-x)=3.00(20) 
2.20x+84-4.20x=60 
+4.20x              -84=      
6.4x divided by itself, cancelling the 6.4, then dividing -24 by the 6.4, I ended up w/ x=-3.75 
** I'm pretty sure I got this wrong. SO could you please help me so I can finish my work? Thanks very much for anything you can give me.!!! 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! Ms. Post wants to mix 2 kinds of cereal. Type A sells at $2.20/lb and Type B sells at $4.20/lb. How many lbs of Type A should she use if she wants a 20 lb mixture selling at $3.00/lb.?  
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Let amt of Type A be "x" ; value of this is 220x cents 
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Amt of Type B is "20-x" ; value of this is 420(20-x) = 8400-420x cents 
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Amt of mixture is 20 lbs. ; value of this is 300*20= 6000 cents 
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EQUATION: 
value + value = value 
220x + 8400-420x = 6000 
-200x = -2400 
 x = 12 lbs (amount of Type A cereal) 
20-x = 8 lbs (amount of Type B cereal) 
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Cheers, 
Stan H. 
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