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

Answer:

#33 1/3# kgm

Explanation:

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

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

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

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

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

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

#rArrcolor(white)("XX")x=100/3 = 33 1/3#