CAT 2022 Slot 3 QA Q4 Ratio, Mixtures & Averages

Question 4 of the Quantitative Ability (QA) section, CAT 2022 Slot 3, with CAT's official answer and a worked solution.

A glass contains 500 cc of milk and a cup contains 500 cc of water. From the glass, 150 cc of milk is transferred to the cup and mixed thoroughly. Next, 150 cc of this mixture is transferred from the cup to the glass. Now, the amount of water in the glass and the amount of milk in the cup are in the ratio
  1. A
    3 : 10
  2. B
    10 : 3
  3. C
    1 : 1
  4. D
    10 : 13

Answer: (C) 1 : 1 Ratio, Mixtures & Averages MCQ

Solution

  1. After the two transfers each vessel again holds 500 cc.
  2. The glass started with 500 cc milk; whatever milk is missing from it (now in the cup) has been replaced by exactly the same volume of water.
  3. So water in glass = milk in cup, ratio \(1:1\).

Shortcut. Back-and-forth transfers with equal final volumes always give equal cross-contamination.

Same concept in other years

See every question on Transferring between two vessels and back: track each liquid.

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