Problema Solution

How many liters of a 12% acid solution must be mixed with 5 liters of a 20% acid solution to give a 14% solution?

Answer provided by our tutors

let volume of sample 1 = x litres

percent of sample 1 = 12 %

Volume of sample 2 = 5 litres

percent of sample 2 = 20 %

Final precent = 14 % 

Final volume will be  =   Volume of sample 1 + Volume of sample 2 =   5  +  x  

 

x * 12 %  +  5 * 20 %   =   (5 + x) * 14 %

or 

12 x  +  100  =  14 * (5 + x)

12 x + 100 = 70  + 14 x

14 x - 12 x = 100 - 70 

2 x = 30 

x = 15 

 

therefore volume of sample 1 =  15 litres   (answer)