Question 181972
The nature center sells bird seed for $0.75 per pound and sunflower seed for $1.10 per pound. To the nearest pound how many pounds of sunflower seed should be used to create a 50-pound mixture that sells for $0.90 per pound?? 
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Equation:
value + value = value
0.75x + 1.10(50-x) = 0.90*50
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Multiply thru by 100 to get:
75x + 110(50-x) = 90*50

75x + 110*50 - 110x = 90*50
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-35x = -20*50

x = 28.57 lb (amt. of 75 cent per pound seed in the mixture)
50 - 28.57 = 21.43 lb (amt. of $1.10 per pound seed in the mixture
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Cheers,
Stan H.