8 Views

Question : P can fill a tank in 5 hours, and Q can fill the same tank in 10 hours. R can empty the same tank in 20 hours. How much time will all the three take together to fill the same tank?

Option 1: 10 hours

Option 2: 4 hours

Option 3: 6 hours

Option 4: 5 hours


Team Careers360 25th Jan, 2024
Answer (1)
Team Careers360 27th Jan, 2024

Correct Answer: 4 hours


Solution : P can fill a tank in 5 hours.
Q can fill the same tank in 10 hours.
R can empty the same tank in 20 hours.
P's per hour efficiency = $\frac{1}{5}$
Q's per hour efficiency = $\frac{1}{10}$
R's per hour efficiency = $- \frac{1}{20}$ (negative because it is emptying the tank)
Total efficiency of P, Q, and R working together = $\frac{1}{5} + \frac{1}{10} − \frac{1}{20}$ = $\frac{5}{20}$ = $\frac{1}{4}$
$\therefore$ Together they will take 4 hours to fill the tank.
Hence, the correct answer is 4 hours.

How to crack SSC CHSL

Candidates can download this e-book to give a boost to thier preparation.

Download Now

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