EduFarming
Your list · 0हिं

Type at least two letters. Press Esc to close.

↑↓ navigate↵ openTAB cycle filter

Boats & Streams, Pipes & Cisterns · Question 69 of 85

Question 69

EasyOriginal question

A pipe fills a tank in 6 hours, and an outlet empties the full tank in 9 hours. If both are open, how long does the empty tank take to fill?

Options for question 69

Show the answer and explanation
CorrectNot quiteAnswer D

Correct answer: D

Explanation

  1. Net rate =16−19=118= \frac{1}{6} - \frac{1}{9} = \frac{1}{18} of the tank an hour.

  2. So the tank fills in 18 hours.

Worth noting

3.6 hours adds the outlet's rate as if it filled too.

Concept
A filling pipe against an outlet
Typical time
60 s
Your time
—
The rule this testsOutlets and leaks
Practise this chapter →

Ten questions from Boats & Streams, Pipes & Cisterns, at your own pace.

Practise this chapter →

Ten questions from Boats & Streams, Pipes & Cisterns, at your own pace.

Practise this chapterAll 85 questions in Boats & Streams, Pipes & CisternsRevise the notes for Boats & Streams, Pipes & Cisterns