SOLUTION: Is it necessary to have a 40% antifreeze solution in the radiator of a certain car. The radiator now has 60 liters of 20% solution. How many liters of this should be drained and re

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Is it necessary to have a 40% antifreeze solution in the radiator of a certain car. The radiator now has 60 liters of 20% solution. How many liters of this should be drained and re      Log On


   

Question 720851: Is it necessary to have a 40% antifreeze solution in the radiator of a certain car. The radiator now has 60 liters of 20% solution. How many liters of this should be drained and replaced with 100% antifreeze to get the desired strength?
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
%2860%2A0.20-u%2A0.20%2Bu%2A1.00%29%2F60=0.40.

The numerator is the amount of resulting pure antifreeze matter, and all concentrations are presented as decimalized fractions. u is the amount of pure antifreeze in liters as well as the amount of the material to remove from the radiator first. Solve for u.