Defence Exam  >  Defence Questions  >  A tank can be filled by pipe X in 2 hours and... Start Learning for Free
A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.? 
  • a)
    12:45 am
  • b)
    5:00 pm
  • c)
    11:45 am
  • d)
    11:50 am
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10...
Suppose the capacity of tank = 6 units (LCM of 2 and 6)
⇒ Efficiency of X = 6/2 = 3 and Efficiency of Y = 6/6 = 1
Pipe X was opened at 10 am and pipe Y is opened at 11 am
Units of water filled by X in 1 hour (10 a.m. to 11 a.m.) = 3 units
⇒ Remaining units of water to be filled = 6 - 3 = 3 units
⇒ Time taken by (X + Y) to fill the remaining tank = ¾ hours = 45 minutes
∴ Tank will get filled at 11:45 a.m.
View all questions of this test
Most Upvoted Answer
A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10...
Solution:

Let's assume that the capacity of the tank is 'C'.

Pipe X can fill the tank in 2 hours.

∴ In 1 hour, pipe X can fill 1/2 of the tank.

Pipe Y can fill the tank in 6 hours.

∴ In 1 hour, pipe Y can fill 1/6 of the tank.

Now, let's calculate the amount of water filled in the tank by pipe X in 1 hour, from 10 a.m. to 11 a.m. (when pipe Y is opened).

Time taken by pipe X from 10 a.m. to 11 a.m. = 1 hour

∴ Amount of water filled by pipe X in 1 hour = 1/2 of the tank

Now, both pipes X and Y are working together.

Combined rate of work = Rate of work of pipe X + Rate of work of pipe Y

= 1/2 + 1/6

= 2/3

∴ In 1 hour, both pipes working together can fill 2/3 of the tank.

Let's assume that the tank gets filled completely after t hours.

Amount of water filled by pipe X from 10 a.m. to t hours = (t-1) × 1/2 of the tank

Amount of water filled by pipe Y from 11 a.m. to t hours = (t-11) × 1/6 of the tank

As both pipes are working together, the sum of the above two amounts should be equal to the capacity of the tank 'C'.

∴ (t-1) × 1/2 + (t-11) × 1/6 = C

Simplifying the above equation, we get:

3t - 23 = 6C

∴ t = (6C + 23)/3

Now, we know that the tank gets filled completely. Hence, C is equal to 1.

∴ t = (6+23)/3

= 29/3 hours

= 9 hours and 40 minutes

Therefore, the tank will be filled at 11:00 a.m. + 9 hours and 40 minutes = 8:40 p.m.

But the question asks for the time at which pipe Y is opened.

Time taken from 11 a.m. to 8:40 p.m. = 9 hours and 40 minutes

∴ The tank will be filled at 11:00 a.m. + 9 hours and 40 minutes = 8:40 p.m.

Therefore, the correct answer is option (c) 11:45 a.m.
Explore Courses for Defence exam
A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer?
Question Description
A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? for Defence 2024 is part of Defence preparation. The Question and answers have been prepared according to the Defence exam syllabus. Information about A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Defence 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer?.
Solutions for A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Defence. Download more important topics, notes, lectures and mock test series for Defence Exam by signing up for free.
Here you can find the meaning of A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer?, a detailed solution for A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? has been provided alongside types of A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A tank can be filled by pipe X in 2 hours and pipe Y in 6 hours. At 10 a.m. pipe X was opened. At what time will the tank be filled if pipe Y is opened at 11 a.m.?a)12:45 amb)5:00 pmc)11:45 amd)11:50 amCorrect answer is option 'C'. Can you explain this answer? tests, examples and also practice Defence tests.
Explore Courses for Defence exam
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev