A chemical supply company has 60 liters of a 40% HNO3 solution. How many liters of pure undiluted HNO3 must the chemists add so that the resultant solution is a 50% solution?	Choose the correct choice from the following options.
A) 12  B) 15  C) 20  D) 24  E) 30
60 liters of a 40% HNO3 solution means HNO3 = 24 liters in 60 liters of the solution.   Now, let x be the pure HNO3 added.   As per question,   24 + x = 50% of (60 + x)   or x =12. Hence, 12
<result>A</result>
A chemical supply company has 60 liters of a 40% HNO3 solution. How many liters of pure undiluted HNO3 must the chemists add so that the resultant solution is a 50% solution?