SOLUTION: An engineer wants to make a 40% cement mixture. How many pounds of a 60% cement mixture must she mix with 12 pounds of a 30% mixture to create a 40% cement mixture?

Question 538397: An engineer wants to make a 40% cement mixture. How many pounds of a 60% cement mixture must she mix with 12 pounds of a 30% mixture to create a 40% cement mixture?

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
An engineer wants to make a 40% cement mixture. How many pounds of a 60% cement mixture must she mix with 12 pounds of a 30% mixture to create a 40% cement mixture?
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Equation:
cement + cement = cement
0.60x + 0.30*12 = 0.40(x+12)
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Multiply thru by 100 to get:
60x + 30*12 = 40x + 40*12
20x = 10*12
x = 6 lbs. (amt. of 60% mixture needed)
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Cheers,
Stan H.
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