Model 3 Opening both taps and leaks Section-Wise Topic Notes With Detailed Explanation And Example Questions
MOST IMPORTANT quantitative aptitude - 3 EXERCISES
The following question based on pipes & cisterns topic of quantitative aptitude
(a) 24 hrs
(b) 36 hrs
(c) 48 hrs
(d) 72 hrs
The correct answers to the above question in:
Answer: (b)
Using Rule 7,
Part of tank emptied by leak in an hour
= $1/36 - 1/24 = {2 - 3}/72 = {–1}/72$
Time taken in emptying the full tank
= 72 hours
Required time = 36 hours
Discuss Form
Read more opening both taps and leaks Based Quantitative Aptitude Questions and Answers
Question : 1
A tap can fill a cistern in 40 minutes and a second tap can empty the filled cistern in 60 minutes. By mistake without closing the second tap, the first tap was opened. In how many minutes will the empty cistern be filled ?
a) 120
b) 108
c) 72
d) 84
Answer »Answer: (a)
Using Rule 7,
Tricky Approach
Part of the cistern filled in 1 minute by both the taps
= $1/40 - 1/60 = {3 - 2}/120 = 1/120$
Empty cistern will be filled in 120 minutes.
Question : 2
Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternatively, the tank will be full in :
a) 7$1/2$ hours
b) 7 hours
c) 6 hours
d) 6$1/2$ hours
Answer »Answer: (b)
Using Rule 1,Two taps 'A' and 'B' can fill a tank in 'x' hours and 'y' hours respectively. If both the taps are opened together, then how much time it will take to fill the tank?Required time = $({xy}/{x + y})$ hrs
Part filled by A and B in 1 hour
= $1/12 + 1/15 = {5 + 4}/60 = 3/20 +$...(i)
Part filled by A and C in the next 1 hour
= $1/12 + 1/20 = {5 + 3}/60 = 2/15$
Part filled in 2 hours
= $3/20 + 2/15 = {9 + 8}/60 = 17/20$
Part filled in 6 hours = $51/60$
Remaining part
= $1 - 51/60 = 9/60 = 3/20$
This part will be filled by (A+B) in 1 hour. [By (i)]
Total time taken = 7 hours
Question : 3
A tap takes 36 hours extra to fill a tank due to a leakage equivalent to half of its inflow. The inflow can fill the tank in how many hours ?
a) 18 hrs
b) 30 hrs
c) 36 hrs
d) 24 hrs
Answer »Answer: (a)
Using Rule 7,
Let the inflow fill the tank in x hours.
$1/x - 1/{2x} = 1/36$
[leakage being half of inflow]
= ${2 - 1}/{2x} = 1/36$
2x = 36
$x = 36/2$ = 18 hours
Question : 4
A cistern is normally filled in 8 hours but takes another 2 hours longer to fill because of a leak in its bottom. If the cistern is full, the leak will empty it in :
a) 40 hours
b) 25 hours
c) 16 hours
d) 20 hours
Answer »Answer: (a)
Using Rule 7,
Part emptied by the leak in 1 hour
= $1/8 - 1/10 = {5 - 4}/40 = 1/40$
The leak will empty the cistern in 40 hours.
Question : 5
A pipe can fill a cistern in 9 hours. Due to a leak in its bottom, the cistern fills up in 10 hours. If the cistern is full, in how much time will it be emptied by the leak ?
a) 100 hours
b) 90 hours
c) 70 hours
d) 80 hours
Answer »Answer: (b)
Using Rule 7,
Part of the tank emptied by the leak in 1 hour
= $1/9 - 1/10 = {10 - 9}/90 = 1/90$
Required time = 90 hours
Question : 6
A tank is fitted with two taps. The first tap can fill the tank completely in 45 minutes and the second tap can empty the full tank in one hour. If both the taps are opened alternately for one minute, then in how many hours the empty tank will be filled completely ?
a) 5 hours 53 minutes
b) 4 hours 48 minutes
c) 2 hours 55 minutes
d) 3 hours 40 minutes
Answer »Answer: (a)
Using Rule 7,
Part of the tank filled in one minute
= $1/45 - 1/60 = {4 - 3}/180 = 1/180$
Since, $1/180$ part is filled in 1 minute
$1 - 1/45 = 44/45$ part is filled in
${2 × 180 × 44}/45$ = 352 minutes
i.e. 5 hours 52 minutes
Remaining $1/45$ part will be filled in 1 minute.
Total time taken = 5 hours 53 minutes
GET pipes & cisterns PRACTICE TEST EXERCISES
Model 1 Basic Pipes & Cisterns problems
Model 2 Filling tank by parts or fractions
Model 3 Opening both taps and leaks
pipes & cisterns Shortcuts and Techniques with Examples
Verbal Reasoning
Question & Answer Quiz
Non Verbal Reasoning
Question & Answer Quiz
Quantitative Aptitude
Question & Answer Quiz
Computer MCQ
Question & Answer Quiz
General English
Question & Answer Quiz
History GK
Question & Answer Quiz
Polity GK
Question & Answer Quiz
Geography GK
Question & Answer Quiz
Economy GK
Question & Answer Quiz
General Awareness GK
Question & Answer Quiz
Recently Added Subject & Categories For All Competitive Exams
100+ Quadratic Equation Questions Answers PDF for Bank
Quadratic Equation multiple choice questions with detailed answers for IBPS RRB SO. more than 250 Attitude practice test exercises for all competitive exams
Continue Reading »
IBPS Aptitude Linear Equations MCQ Questions Answers PDF
Linear equations multiple choice questions with detailed answers for IBPS RRB SO. more than 250 Attitude practice test exercises for all competitive exams
Continue Reading »
New 100+ Compound Interest MCQ with Answers PDF for IBPS
Compound Interest verbal ability questions and answers solutions with PDF for IBPS RRB PO. Aptitude Objective MCQ Practice Exercises all competitive exams
Continue Reading »
100+ Mixture and Alligation MCQ Questions PDF for IBPS
Most importantly Mixture and Alligation multiple choice questions and answers with PDF for IBPS RRB PO. Aptitude MCQ Practice Exercises all Bank Exams
Continue Reading »