SOLUTION: A light green latex paint that is 20% yellow paint is combined with a darker green latex paint that is 45% yellow paint. How many gallons of each paint must be used to create 50 ga

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A light green latex paint that is 20% yellow paint is combined with a darker green latex paint that is 45% yellow paint. How many gallons of each paint must be used to create 50 ga      Log On


   



Question 759859: A light green latex paint that is 20% yellow paint is combined with a darker green latex paint that is 45% yellow paint. How many gallons of each paint must be used to create 50 gallons of a green paint that is 25% yellow paint?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = gallons of 20% yellow paint needed
Let +b+ = gallons of 45% yellow paint needed
+.2a+ = gallons of yellow paint in 20% yellow paint
+.45b+ = gallons of yellow paint in 45% yellow paint
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(1) +a+%2B+b+=+50+
(2) +%28+.2a+%2B+.45b+%29+%2F+50+=+.25+
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(2) +.2a+%2B+.45b+=+.25%2A50+
(2) +.2a+%2B+.45b+=+12.5+
(2) +20a+%2B+45b+=+1250+
Multiply both sides of (1) by +20+
and subtract (1) from (2)
(2) +20a+%2B+45b+=+1250+
(1) +-20a+-+20b+=+-1000+
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+25b+=+250+
+b+=+10+
and, since
(1) +a+%2B+b+=+50+
(1) +a+%2B+10+=+50+
(1) +a+=+40+
40 gallons of 20% yellow paint are needed
10 gallons of 45% yellow paint are needed
check:
(2) +%28+.2a+%2B+.45b+%29+%2F+50+=+.25+
(2) +%28+.2%2A40+%2B+.45%2A10+%29+%2F+50+=+.25+
(2) +%28+8+%2B+4.5+%29+%2F+50+=+.25+
(2) +12.5+=+.25%2A50+
(2) +12.5+=+12.5+
OK