Pipes and Cisterns for SSC CGL | Concepts & Practice

Learn the shortcut

Understand the fastest pattern for this topic before you attempt full MCQs.

Avoid common traps

See where students commonly lose marks so you can eliminate bad options earlier.

Solve faster in exam

Apply one practical method before attempting MCQs and cut down hesitation.

Summary Formula Tricks Mistakes Solved Example Practice FAQ

Pipes and Cisterns revision for SSC CGL: understand the base rule, apply the correct formula or relation, check common traps, then practise with approved questions.

Pipes and Cisterns is a rate problem. Filling pipes contribute positive work; emptying pipes contribute negative work. Add their rates, not their times.

SSC CGL focus: Solve the core method first, then use the approved practice questions on this page to build exam-speed accuracy.

Pipes and Cisterns revision rule: concept → formula/relation → one worked example → timed practice → error review.

Core concept
Key formula/relation
Common trap
Approved practice

If a pipe fills in x hours, rate = 1/x
If an outlet empties in y hours, rate = -1/y
Net time = 1 / net rate

Use an LCM-based tank capacity when the times are clean integers; it converts fractions into simple unit rates.

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You can start learning here right away, explore formulas and tricks, and use the current limited practice flow before premium tools arrive.

Read the exact requirement before choosing a shortcut.
Keep units, signs and percentage bases consistent.
Use the final few seconds to verify direction and magnitude.

Using a memorised shortcut without checking its condition.
Skipping unit or base conversion.
Doing long arithmetic before identifying the underlying relation.

Practice example: A pipe fills a tank in 15 hours and another fills it in 10 hours. A leak empties it in 30 hours. How long will the tank take to fill when all are open?

Solution: The tank fills in 15/2 hours.

A pipe can fill a tank in 12 hours. What fraction of the tank will it fill in 3 hours?
Pipe A can fill a tank in 10 hours and Pipe B can fill it in 15 hours. If both are opened together, in how many hours will the tank be filled?
A pipe fills a tank in 8 hours, while an outlet empties it in 24 hours. If both are opened together, how long will the tank take to fill?

Learn the shortcut first

Shortcut before you solve

Pipes and cisterns uses time-and-work rate logic with outlet rates subtracted.

Faster solving steps

Use this 4-step method before solving to keep your thinking fast and repeatable.

Step 1 Identify relation

Spot the pattern, relationship, or core idea first.

Step 2 Apply same pattern

Use the same rule instead of re-solving from scratch.

Step 3 Eliminate wrong options

Remove confusing choices before comparing the last few.

Step 4 Confirm final answer

Pick the option that matches the shortcut most cleanly.

Practice Questions

Start with the first 10 questions free, then unlock the rest with premium

Now apply the trick on real questions

Use the shortcut above before solving these questions

Convert each pipe into a one-hour rate; filling is positive and emptying is negative.

Tip: A pipe filling a tank in 6 hours fills 1/6 of it per hour.

Step 1

Take the full tank as 1.

Step 2

One-hour filling rate = 1/6.

Rule

Net rate = total inlet rate - total outlet rate.

3-second trick

Convert every completion time into an hourly rate first.

Trap to avoid

Do not add filling times directly.

Correct answer

1/6

Thinking path

The full tank is one unit.
Six hours means one-sixth per hour.
Multiple pipes must be combined through rates.

Final answer: 1/6

Why this is fast: Rate form makes inlet and outlet problems straightforward.

Free now: first 10 questions Premium later: full solutions, advanced tricks, targeted practice

Q1 Easy

A pipe fills 3/5 of a tank in 6 hours. How long will it take to fill the whole tank at the same rate?