It is necessary to have a 40% antifreeze solution in the radiator of a certain car. the radiator now has 70 liters of 20% solution. how many liters of this shou
Chemistry
brennan5308
Question
It is necessary to have a 40% antifreeze solution in the radiator of a certain car. the radiator now has 70 liters of 20% solution. how many liters of this should be drained and replaced with 100% antifreeze to get the desired strength?
2 Answer

1. User Answers lilaipo
The answer is : 17.5 liters drained and replaced by 17.5 liters of 100% solution.
x = amount drained and replaced
(70x) = remaining amount of 20% solution
.20(70x) + 1.00(x) = .40(70)
14  .2x + 1x = 28
1x  .2x = 28  14
.8x = 14
x = 14/.8
x= 17,5 ( 17.5 liters drained and replaced by 17.5 liters of 100% solution) 
2. User Answers oyesobas912
Answer:
17.5 litres removed and 17.5 litres of pure antifreeze added
Explanation:
Let k equal the amount of the solution to be removed
amount of antifreeze to be added
0.2(70  x) + x = 0.4(70)
14  0.2x +x = 28
0.8x = 28 14
x = 14/0.8 = 17.5
x = 17.5 litres removed and 17.5 litres of pure antifreeze added