Question 449381
4x.4=1.6
.25(4-x)+x=1.6
1-.25x+x=1.6
.75x=.6
x=.6/.75=.8
The mechanic need to remove .8 gallons of the anti-freeze he/she's got in the radiator, and replace it with .8 gallons of pure antifreeze to get the desired solution.