How many liters of a 40% iodine solution need to be mixed with 35 liters of a 20% iodine solution to create a 35% iodine solution?
Choose the correct choice from the following choices
A) 35 B) 49 C) 100 D) 105 E) 140
Solution 1:   Assume the iodine solution to be mixed = x lts.   Iodine = 0.4x lts, Water = 0.6x lts.   Solution 2: 35 liters of a 20% iodine solution   Iodine = 7 lts, Water = 28 lts.   Total iodine = 0.4x + 7   Total water = 0.6x + 28   The resultant is a 35% iodine solution.   Hence (0.4x + 7) / (x + 35) = 35/100   40x + 700 = 35x + 1225   5x = 525   x = 105 lts   Correct Option: 105
<result>D</result>
How many liters of a 40% iodine solution need to be mixed with 35 liters of a 20% iodine solution to create a 35% iodine solution?