CLEAR
Toprankers-Info

+91 7676564400

Mobile App

Get it on Google Play
Discussions
Select Date
Tags:

Articles

Discussions
Submit Discussion
amit

· started a discussion

· 1 Months ago

itna lenghty (Question: 83303.0 )

wrong h bilkul hi yr

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. First A and B are opened. After 7 minutes, C is also opened. Now,the tank is filled in the next:

Options:
A) 39 minutes
B) 46 minutes
C) 40 minutes
D)

45 minutes


Solution:

Ans:(a)

Pipe A can fill empty tank in 30 min.

Pipe A can fill the tank = 100/36 = 2.77% per minute.

Pipe B can fill empty tank in 45 min.

Pipe B can fill the tank = 100/45 = 2.22% per min.

A and B can together fill the tank,

= (2.77 + 2.22)= 5% per minute.

So, A and B can fill the tank in 7 min.,

= 7*5 = 35% of the tank.

Rest tank to be filled = 100 - 35 = 65%.

C can empty the full tank in 30 min.

C can empty the tank = 100/30 = 3.33% per min.

C is doing negative work i.e. emptying the tank.

A, B and C can together fill the tank,

= 2.77% + 2.22% - 3.33% = 1.67% tank per minute.

So, A, B and C will take time to fill 65% empty tank,

= 65/1.67 = 39 min. (Approx.)

Knowledge Expert

· commented

· 1 Months ago

Dear Student

Another Trick-
Tank fill by both pipe A and B in one min. = 1/36+ 1/45 = 1/20 part of the tank
If both pipes open for 7 min = 1/20 * 7 = 7/20 part.
remaining Part after 7 min = 1- (7/20) = 13/20

Tank filled by pipes A,B and c are opened at the time = (1/36 +1/45 -1/30)= 1/60 Part

1/60 part of tank filled by all pipes in one min,

Time required for fill the remaining part (13/20)= (13/20)/ 1/60
= 39 min.

I Hope you got it.
-logo
We at aim to provide most comprehensive content & test for practice which is carefully divided into various chapters and topics to help you focus on your weak areas.Our Practice mock test gives you unmatched analytics to help you realize your strong areas,time management and improvement areas.Our Short & Crisp notes on each topic will help you to quickly revise the topic along with the tips & tricks of the exams.
More About
-Info
-Info

Mobile App

Get it on Google Play
About Us Campus Ambassador Careers Contact Us Refund Policy

All Rights Reserved Top Rankers

User Policy
Disclaimer
Terms & Conditions