Problema Solution
The cooling system of a car has a capacity of 15 liters. If the system is currently filled with a mixture that is 60% antifreeze, how much of this mixture should be drainded and replaced with pure antifreeze so that the system is filled with a solution that is 80% antifreeze?
Answer provided by our tutors
at the beginning the antifreeze is 60%
so it has 60% * 15 = 9 liters
it changes to 80% it means need 80% * 15 = 12 liters
so 3 liters should be drained and replaces with pure antifreeze