Question 982455
The description implies that the capacity of the radiator is greater, larger than 8 quarts.


Has 10%; wants  or needs 20%;


Let v be amount of pure antifreeze to add.
{{{(8*(0.1)+v*(1.0))/(v+8)=0.2}}}, setup using decimal fractions instead of percents;


{{{(8+10v)/(v+8)=2}}}, simply multiplied both sides by 10


{{{10v+8=2(v+8)}}}
and again,...


{{{5v+4=v+8}}}


{{{v+4=8}}}


{{{highlight(v=4)}}}, how many quarts of pure antifreeze to add.