Two kinds of workers or pipes in two combinations: solve for unit rates

CAT has tested this idea 4 times across 3 papers, from 2018 to 2019. 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 2018 Slot 1 · QA Q31	6 fill/5 drain vs 5 fill/6 drain; time for 2 fill/1 drain	10
CAT 2018 Slot 2 · QA Q27	inlets of types A and B in two combinations	48
CAT 2018 Slot 1 · QA Q28	humans and robots in two team mixes	B
CAT 2019 Slot 1 · QA Q30	men and machines; one setup takes half the other's time	13

Part of Time & Work (34 questions since 2017).