Work and Time: Three Inlet Pipes and a Drain Quiz — 5 Free Questions

📖 Read the passage, then answer the questions below

A water treatment facility has three inlet pipes, P, Q, and R, and one outlet drain pipe, S, all connected to the same large storage tank. Pipe P alone can fill the empty tank in 10 hours. Pipe Q alone can fill the empty tank in 15 hours. Pipe R alone can fill the empty tank in 30 hours. The outlet drain, Pipe S, when opened alone on a completely full tank, can empty it entirely in 12 hours.

On a particular day, to test how the system behaves under realistic operating conditions, the facility's operators opened Pipe P, Pipe Q, and the outlet drain Pipe S all together at the same time, starting with a completely empty tank, and let the combined system run without any further changes. The operators are now reviewing the results of this test alongside several other possible pipe combinations, to decide which combination of pipes should be used during future routine operations at the facility.

Question 1

What is the combined rate, as a fraction of the tank per hour, of Pipe P and Pipe Q together?

Question 2

What fraction of the tank does Pipe P fill in 3 hours?

Question 3

If Pipe P and Pipe S are opened together on an empty tank, with Pipe P filling and Pipe S draining, how long will it take to fill the tank?

Question 4

If Pipe P alone runs for 5 hours, what fraction of the tank remains empty?

Question 5

What is the ratio of the time taken by Pipe Q alone to the time taken by Pipe S alone to complete its respective task?

📚 All Quizzes

Browse every category and see the full list of quizzes on BriskQuiz

→

About Work and Time: Three Inlet Pipes and a Drain

CLAT's Quantitative Techniques section pairs a short data-rich scenario with several straightforward numeric questions -- here, work and time applied to a single invented plumbing system, so every answer can be worked out from the figures given, without any outside knowledge.

This quiz is built around one storage tank: three inlet pipes and one outlet drain, each with its own fill or drain rate, fully worked out up front. Every question below is answered using those same rates -- nothing new is introduced question to question.

The twenty-four questions move through the kind of angles CLAT actually tests: individual pipe rates, combined rates for different groups of pipes, fractions of the tank filled in a given time, ratios between pipes, and a multi-statement combination question.

Only five of the twenty-four questions are shown on any single attempt, so replaying this quiz brings a genuinely different mix of angles on the same tank rather than the same five memorised by rote.