Quantitative Aptitude – Pipes & Cistern
Calculate filling and emptying rates accurately using combined work logic.
1. Concept
An inlet pipe fills and outlet pipe empties. Net rate = sum(inlet rates) − outlet rate.
2. Formula
If inlet fills in a days and b days, and outlet empties in c days: net rate = \(1/a + 1/b - 1/c\). Time to fill = \(1 / \text{net rate}\).
3. Quick Tips
4. Mistakes to Avoid
5. Revision Checklist
Summary: Model pipes as work rates, combine correctly and solve for time with rate inversion.