Virginia and Campbell had 100 kilograms of a 20% glycol solution. How much of a 40% glycol solution should be added to get a solution that is 35% glycol?

1 Answer
Oct 9, 2015

33 1/33313 kgm

Explanation:

Suppose we need to add color(red)(x)x kgm of color(red)(40%)40% glycol to the color(blue)(100)100 kgm of color(blue)(20%)20% glycol solution

The resulting mass would be color(green)((100+x))(100+x) kgm (at a concentration of color(green)(25%)25%)

color(blue)(20% xx 100) + color(red)(40% xx x) = color(green)(25% xx (100+x))20%×100+40%×x=25%×(100+x)

rArrcolor(white)("XX")color(blue)(20)+color(red)(2/5x) = color(green)(25+1/4x)XX20+25x=25+14x

rArrcolor(white)("XX")(color(red)(2/5)-color(green)(1/4))x = color(green)(25)-color(blue)(20)XX(2514)x=2520

rArrcolor(white)("XX")3/20x= 5XX320x=5

rArrcolor(white)("XX")x=100/3 = 33 1/3XXx=1003=3313