Pipes and Cistern- Aptitude Questions and Answers

View in English View in Hindi

Three pipes A, B and C together can fill a cistern in 6 hours. After working together for 2 hours, C is closed and A and B fill the remaining cistern in 8 hours. Then the time in which the cistern can be filled by pipe C alone will be:

A)
11 hours

B)
9 hours

C)
12 hours

D)
10 hours


Correct Answer :

12 hours


Explanation :

Three Pipes A,B and C together filled a tank in 6 hours
So 1 hour work of A,B and C =1/6
C closed after 2 hour's, Part filled in 2 hours working together(A,B and C) = 2/6 = 1/3
Remaining part = (1-1/3) = 2/3

A and B can fill remaining in 8 hours, (A + B)'s 8 hour's work = 2/3

So, (A+B)'s 1 hour work = 2/24=1/12

Therefore C's 1 hour's work
= [(A+B+C)'s 1 hour]-[(A+B)'s 1 hr work]
=(1/6 - 1/12) = 1/12

C alone can fill the tank in 12 hours

Two pipes A and B can fill a cistern in 4 and 6 minutes respectively. If both the pipes kept turned on alternatively for one minute each starting from A, how long will it take to fill the cistern?

A)
3(3/7) minutes

B)
6 minutes

C)
4(2/3) minutes

D)
6(6/7) minutes


Correct Answer :

4(2/3) minutes


Explanation :

As the pipes are operating alternatively for one minute, thus (A+B)'s 2 minutes job is =(1/4 +1/6) =5/12
in next, 2 minutes both pipe can fill another 5/12 part.
So in 4 minutes A and B are operating alternatively will fill 5/12 + 5/12 = 5/6

Remaining part of cistern= 1 - 5/6 =1/6

Pipe A can fill 1/4 part of the cistern in 1 minute,and can fill 1/6 part of the cistern in = 4*(1/6) =2/3 minutes

Total time taken to fill the Cistern = time taken to fill (5/6 part + 1/6 part)
=> 4 minutes + 2/3 minutes = 4(2/3) minutes Or, 4 minutes 40 seconds

Pipe A can fill a tank in 45 hrs and pipe B can fill it in 36 hrs. If both the pipes are opened in the empty tank. In how many hours will it be full?

A)
10 hr

B)
15 hr

C)
20 hr

D)
28 hr


Correct Answer :

20 hr


Explanation :

If a pipe can fill a tank in x hours, then : part filled in 1 hour = 1/x

Part filled A in 1 hr= (1/45)
Part filled B in 1 hr= (1/36)
Part filled by (A+B) together in 1 hr=(1/45)+(1/36)=1/20

So, The tank will be full in 20 hr.

If a pipe fills a tank in 6 h, then what part of the tank will the pipe fill in 1 h?

A)
1/3

B)
1/6

C)
1/4

D)
1/5


Correct Answer :

1/6


Explanation :

If a pipe can fill a tank in x hours, then : part filled in 1 hour = 1/x

Then,when a pipe fills a tank in 6 h, then the part of tank filled in 1 h = 1/6
Hence ,required part of the tank to be filled in 1h = 1/6 part

A tap can fill a tank in 16 minutes and another can empty it in 8 minutes. If the tank is already half full and both the taps are opened together, the tank will be ?

A)
Filled in 12 min

B)
Emptied in 12 min

C)
Filled in 8 min

D)
Emptied in 8 min


Correct Answer :

Emptied in 8 min.


Explanation :

If a pipe can fill a tank in x hours and another pipe can empty the full tank in y hours (where x > y), then on opening both the pipes, the net part emptied in 1 hour = (1/y)-(1/x)

= (1/8 - 1/16) = 1/16
Time taken to empty the full tank = 16 min.
Hence, time taken to empty the half tank = 8 min

One tap can fill a cistern in 2 hours and another can empty the cistern in 3 hours. How long will they take to fill the cistern if both the taps are opened ?

A)
5 hours

B)
6 hours

C)
7 hours

D)
8 hours


Correct Answer :

6 hours


Explanation :

If a pipe can .fill a tank in x hours and another pipe can empty the full tank in y hours (where y> x), then on opening both the pipes, the net part filled in 1 hour = (1/x)-(1/y)

= (1/2 - 1/3) = 1/6
Hence, time taken to fill the cistern = 6 hours

44 pipes can fill a large water tank in 27 hours. How many hours it take for 66 pipes to fill four such tanks ?

A)
72

B)
54

C)
63

D)
84


Correct Answer :

72


Explanation :

44 pipes => 27 hours
66 pipes=> ?

Amount of work done is same for filling a pipe, So
44*27 = 66*X
X = 44*27 / 66
X = 18
66 pipes can fill one tanks in 18 hours.
they will fill 4 tanks in 18*4 = 72 hours

Latest Updates

Percentage

20% of a quantity is Rs 400, the quantity equals?

Time and Work

A certain piece of work can be completed by 12 men in 9 days. After they have worked for six days, six more men joined them. How many days will it take to complete the remaining work?

Ratio and Proportion

A certain sum was divided among A, B and C in the ratio 5 : 7 : 6. If B received Rs 4500 more than C, find C's share?

Problems on Ages

A is two years older than B who is twice as old as C. If the total of the ages of A, B and C be 27, the how old is A?

Time and Work

A and B can together finish a work in 30 days. They worked at it for 20 days and then B left. The remaining work was done by A alone in 20 more days. B alone can do the entire work in?

Discount

A retailer buys a washing machine marked at Rs 4800 and gets two successive discounts of 15% and 5%. If he spends Rs 124 on transportation and sells the washing machine at a gain of 13%, then find the selling price of the machine.

Boats and Streams

Speed of a boat in still water is 10 kmph, and speed of the stream is 5 Kmph. In how many minutes would the boat cover a distance of 5 km downstream?

Problems on Ages

The age of two persons differ by 2 years. If the sum of their ages is equal to the square root of 144 then find the age of the elder among the two person?

The age of A is six times the age of his son. A's father is 40 years older than him. Together, they are 118 years old. What is the age of A?

Average

The average mark of 50 students is 75. If the marks obtained by one of the student had been written as 36 instead of 86, then the corrected average of marks is:

Unix/Linux

What is inode?

Problems on Ages

A group of 15 people has average age of 45 years. Two persons are excluded and the average of the remaining is increased by 5 years. What is the average age of the two persons who have been excluded?

Average

In the world cup, Yuvraj has a batting average of 65 in 7 matches till semi-final. How much should Yuvraj score in the 8th match ie the final match to get a batting average of 85?

Problems on Trains

A train takes 8 sec to cross a 75 metre long platform at a speed of 90 km/h. What is the length of the train?

Alligation or Mixture

In what ratio must Rs 50 per kg salt be mixed with Rs 80 per kg salt to obtain a mixture worth of Rs 60 per kg?

Numbers

Find the sum of the given series: 3 + 9 + 27 + 81 + 243 + 729 + 2187 + 6561

Average

Find the average. 62, 54, 44, 36, 28 & 22

Percentage

In an examination, 36% of the students failed in English and 40% failed in Hindi. If 20% of the students failed in both subjects, then the pass percentage is?

Latest Job Notifications

Jobs in Madhya Pradesh

राष्ट्रीय स्वास्थ्य मिशन मध्य प्रदेश National Health Mission MP(NRHM) - 5215 पद - 22/06/2021 अंतिम तिथि

Jobs in Punjab

पंजाब स्टेट पावर कॉर्पोरेशन लिमिटेड Punjab State Power Corporation Limited (PSPCL) - 2632 पद - 20/06/2021 अंतिम तिथि

Jobs in Chhattisgarh

स्वास्थ्य सेवा निदेशालय, छत्तीसगढ़ Department of Health & Family Welfare, Chhattisgarh - 267 पद - 26/06/2021 अंतिम तिथि

Government Jobs

दिल्ली सबऑर्डिनेट सर्विस सिलेक्शन बोर्ड Delhi Subordinate Services Selection Board(DSSSB) - 5807 पद - 03/07/2021 अंतिम तिथि

Jobs in Madhya Pradesh

राष्ट्रीय स्वास्थ्य मिशन मध्य प्रदेश National Health Mission MP(NRHM) - 2850 पद - 31/05/2021 अंतिम तिथि

Government Jobs

इंडियन पोस्ट सर्विस Indian Post Service - 4368 पद - 29/05/2021 अंतिम तिथि

दिल्ली सबऑर्डिनेट सर्विस सिलेक्शन बोर्ड Delhi Subordinate Services Selection Board(DSSSB) - 7236 पद - 24/06/2021 अंतिम तिथि

Banking Jobs

Reserve Bank of India (RBI) - 841 Posts - 15/03/2021 Last date

Institute of Banking Personnel Selection (IBPS) - CRP SPL-IX - 1163 Posts - 26/11/2019 Last date

Government Jobs

Reserve Bank of India (RBI) - 199 Posts - 11/10/2019 Last date