The radiator of an automobile is filled to capacity with 8 liters of a solution that is 20% liquid x. The automobile engine overheats, and 6 liters of water evaporate, leaving 2 liters of concentrated liquid x solution If the radiator is refilled with 6 liters of a solution that is 20% liquid x, what will be the concentration of the resulting solution ?
Assuming that the solution contains only liquid X and water.
Lets solve this in a step wise fashion :
step 1: radiator is filled with 8 liter solution which is 20% x.
So x = 0.2* 8 = 1.6 liters, following this water = 8 -1.6 liter = 6.4 liters.
step 2: 6 liters of water is evaporate.
so what we have left is :
x = 1.6 liter and water = 0.4 liter
totaling to 2 liters of solution.
step 3 : 6 liters of 20% solution x is added.
In the 6 liters of the above mentioned solution, we have 1.2 liter X and 4.8 liter water.
Adding it to the solution obtained from step 2 we have :
2.8 liter x and 5.2 liter water solution.
totaling to 8 liter of solution.
step 4: calculate the percentage of X
\(\frac{2.8}{8 }* 100 = 7 * 5 = 35\)%
Hence IMO option D.