<PRE><B>Question 321955</B>
John used 5 gallons of BLUE paint and 8 gallons of WHITE John spent $197
Kim used only 3 gallons of BLUE, but 11 gallons of WHITE  Kim spent $205, 

Let  blue paint cost $x/gallon
Let White paint cost $y per gallon
..
John
5x+8y=197.......... equation 1
Kim
3x+11y=205......... equation 2
multiply equation 1 by 3 and equation2 by 5 to eliminate x
..
15x+24y=591
15x+55y=1025
Subtract
15x+24y-15x-55y=591-1025
-31y=-434
y=434/31
y=14 dollars - cost of white paint / gallon
plug the value of y in equation 1
5x+8*14=197
5x=197-112
5x=85
x=17 dollars the cost of blue paint - 
One more migraine gone I suppose
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