31 Views

Question : Two pipes, A and B, can fill a tank in 36 minutes and 45 minutes, respectively. Another pipe, C, can empty the tank in 30 minutes. Initially, pipes A and B are opened. After 7 minutes, pipe C is also opened. The tank is then filled up in:

Option 1: 39 minutes

Option 2: 46 minutes

Option 3: 40 minutes

Option 4: 45 minutes


Team Careers360 21st Jan, 2024
Answer (1)
Team Careers360 24th Jan, 2024

Correct Answer: 46 minutes


Solution : Time taken by A to fill the tank = 36 minutes
Part of tank filled by A in a minute = $\frac{1}{36}$
Time taken by B to fill the tank = 45 minutes
Part of tank filled by B in a minute = $\frac{1}{45}$
Time taken by C to empty the tank = 30 minutes
Part of tank emptied by C in a minute = $\frac{1}{30}$
Part of the tank filled by A and B in the first 7 minutes = ($\frac{1}{45}$ + $\frac{1}{36}$) × 7
= $\frac{9}{180}$ × 7 = $\frac{7}{20}$
The remaining part of the tank filled by A, B, and C together = 1 – $\frac{7}{20}$ = $\frac{13}{20}$
Part of the tank filled by A, B, and C together in a minute = ($\frac{1}{45}$ + $\frac{1}{36}$) – $\frac{1}{30}$
= $\frac{9 – 6}{180}$ = $\frac{1}{60}$
Time taken to fill the remaining part of tank = $\frac{\frac{13}{20}}{\frac{1}{60}}$ = 39 minutes
Total time taken to fill the tank = 7 + 39 = 46 minutes
Hence, the correct answer is 46 minutes.

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