how much shoulder be drained

Question

An automobile radiator holds 24 liters of fluid. There is currently a mixture in the radiator that is 70% antifreeze and 30% water. How much of this mixture should be drained and replaced by pure antifreeze so that the resulting mixture is 80% antifreeze?

Answer 1

0.7(24) = 16.8

 

0.8(24) = 19.2

 

19.2 - 16.8 = 2.4 oz

 

Or, 80% - 70% = 10% = 0.1

 

0.1(24) = 2.4 oz