Multiple choice

A chemist has two containers A and B of equal volumes of 35 litres each. Container A initially contains a mixture of X and water in the ratio 2 : 3, while container B initially contains a mixture of Y and water in the ratio 3 : 4. The chemist decides to prepare a mixture in which the concentration of liquids X and Y should be 33 1 3 % of the total solution. However, while transferring the liquids, the chemist accidentally pours 20% of the mixture from container A and 30% of the mixture from container B. Now how much water should be mixed in the resultant mixture to get the targeted result?

  1. 2.2 litres

  2. 2.4 litres

  3. 4.4 litres

  4. 5.8 litres

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Container A: 20% of 35L = 7L (2.8L X, 4.2L water). Container B: 30% of 35L = 10.5L (4.5L Y, 6L water). Total mixture = 17.5L. Total X+Y = 7.3L. Targeted concentration 1/3 means 7.3L is 1/3 of total volume. Total volume = 21.9L. Water needed = 21.9 - 17.5 = 4.4L.

AI explanation

Pouring 20% of mixture from container A means transferring 7 liters, containing 2.8 liters of X and 4.2 liters of water. Pouring 30% of mixture from container B means transferring 10.5 liters, containing 4.5 liters of Y and 6 liters of water. The total resulting mixture is 17.5 liters, and to achieve a 33.33% concentration of X and Y, the required amount of these liquids must be 17.5 / 3 = 5.833 liters; since the available amount is 2.8 + 4.5 = 7.3 liters, the required amount of water to be mixed is 17.5 - 5.833 - 7.3 = 4.367 liters.