21 Views

Question : Pipes A and B running together can fill a cistern in 6 minutes. If B takes 5 minutes more than A to fill the cistern, then what will be the respective time in which A and B will fill the cistern separately?

Option 1: 15 min and 10 min

Option 2: 15 min and 20 min

Option 3: 25 min and 20 min

Option 4: 10 min and 15 min


Team Careers360 16th Jan, 2024
Answer (1)
Team Careers360 20th Jan, 2024

Correct Answer: 10 min and 15 min


Solution : Let the time taken by A to fill the cistern be $x$ minutes.
So, the time taken by B to fill the cistern is $x+5$ minutes.
Time taken by A and B to fill the cistern = 6 minutes
Part of cistern filled by A and B in a minute $= \frac{1}{6}$
Part of cistern filled by A in a minute $= \frac{1}{x}$
Part of cistern filled by B in a minute $=\frac{1}{x+5}$
Part of cistern filled by A and B together in a minute $= \frac{1}{x}+\frac{1}{x+5}$
⇒$\frac{1}{x}+\frac{1}{x+5}=\frac{1}{6}$
⇒ $12x+30=x^2+5x$
⇒ $x^2-7x-30=0$
⇒ $x=-3,10$
$\therefore x=10$ (–3 is neglected because time can't be negative)
Time taken by B = 10 + 5 = 15 min
Hence, the correct answer is '10 min and 15 min'.

SSC CGL Complete Guide

Candidates can download this ebook to know all about SSC CGL.

Download EBook

Know More About

Related Questions

TOEFL ® Registrations 2024
Apply
Accepted by more than 11,000 universities in over 150 countries worldwide
Manipal Online M.Com Admissions
Apply
Apply for Online M.Com from Manipal University
View All Application Forms

Download the Careers360 App on your Android phone

Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile

150M+ Students
30,000+ Colleges
500+ Exams
1500+ E-books