SOLUTION: How many gallons of a 70​% antifreeze solution must be mixed with 90 gallons of 25​% antifreeze to get a mixture that is 60​% ​antifreeze? Use the​ si

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Question 1035980: How many gallons of a 70​% antifreeze solution must be mixed with 90 gallons of 25​% antifreeze to get a mixture that is 60​% ​antifreeze? Use the​ six-step method. can you help me do this type proble?
Found 2 solutions by josmiceli, stanbon:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
I don't know what the 6-step method is, but
this is how I do it:
Let +x+ = gallons of 70% antifreeze needed
+.25%2A90+=+22.5+ gallons of pure antifreeze in 25% solution
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+%28+.7x+%2B+22.5+%29+%2F+%28+x+%2B+90+%29+=+.6+
+.7x+%2B+22.5+=+.6%2A%28+x+%2B+90+%29+
+.7x+%2B+22.5+=+.6x+%2B+54+
+.1x+=+31.5+
+x+=+315+
315 gallons of 70% antifreeze are needed
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check:
+%28+.7x+%2B+22.5+%29+%2F+%28+x+%2B+90+%29+=+.6+
+%28+.7%2A315+%2B+22.5+%29+%2F+%28+315+%2B+90+%29+=+.6+
+%28+220.5+%2B+22.5+%29+%2F+405+=+.6+
+243+=+.6%2A405+
+243+=+243+
OK

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
How many gallons of a 70​% antifreeze solution must be mixed with 90 gallons of 25​% antifreeze to get a mixture that is 60​% ​antifreeze? Use the​ six-step method. can you help me do this type proble?
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Equation::
anti + anti = anti
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0.70x + 0.25*90 = 0.60(x + 90)
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70x + 25*90 = 60x + 60*90
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10x = 35*90
x = 9*35
x = 315 gallons (amt. of 70% solution needed)
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Cheers,
Stan H.
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