Transferring between two vessels and back: track each liquid

CAT has tested this idea 4 times across 4 papers, from 2019 to 2025. Solve one, and the others are the same method with different numbers or wording, which is why repeated concepts are the most efficient thing to practise.

Question	What it asks	Answer
CAT 2022 Slot 3 · QA Q4	150 cc milk to water cup and back; water in glass equals milk in cup	C
CAT 2025 Slot 3 · QA Q22	alcohol to water and back; final ratio 15:4, find volume moved	16
CAT 2022 Slot 2 · QA Q6	half-filled containers, three successive half transfers	A
CAT 2019 Slot 2 · QA Q30	three vessels A to B to C to A, salt strengths	D

Part of Ratio, Mixtures & Averages (84 questions since 2017).