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Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:
  • a)
    60 gallons
  • b)
    100 gallons
  • c)
    120 gallons
  • d)
    180 gallons
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
Two pipes can fill a tank in 20 and 24 minutes respectively and a wast...
Work done by the waste pipe in 1 minute
=1/15 – (1/20 + 1/24)
= (1/15 – 11/20)
= – 1/40 [–ve sign means emptying]
∴ Volume of 1/40 part = 3 gallons
Volume of whole = (3 × 40) gallons
= 120 gallons
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Most Upvoted Answer
Two pipes can fill a tank in 20 and 24 minutes respectively and a wast...
To solve this problem, we can use the concept of rates. Let's say the capacity of the tank is x gallons.

Given information:
- Pipe A can fill the tank in 20 minutes, so its filling rate is x/20 gallons per minute.
- Pipe B can fill the tank in 24 minutes, so its filling rate is x/24 gallons per minute.
- The waste pipe can empty 3 gallons per minute.

Working together:
When all three pipes are working together, the net filling rate is the sum of the filling rates of the two pipes minus the emptying rate of the waste pipe.

Net filling rate = (x/20 + x/24) - 3 gallons per minute

We are given that when all three pipes work together, they can fill the tank in 15 minutes. So, we can set up the equation:

x/15 = (x/20 + x/24) - 3

Simplifying the equation:
To simplify the equation, we can multiply through by the common denominator, which is 120:

8x + 10x - 360 = 15x - 3*120

18x - 360 = 15x - 360

18x - 15x = -360 + 360

3x = 0

x = 0/3

x = 0

Since the capacity of the tank cannot be zero, there must be an error in our calculations.

Revisiting the information:
Let's check the given information again. It is mentioned that the waste pipe can empty 3 gallons per minute. However, it is not clear whether the waste pipe is active or not when all three pipes are working together. If the waste pipe is not active, it means it is not emptying any water, and our equation should be:

x/15 = x/20 + x/24

Simplifying this equation:
Again, we can multiply through by the common denominator, which is 120:

8x + 10x = 12x

18x = 12x

6x = 0

x = 0/6

x = 0

Again, we obtain zero as the capacity of the tank, which is not possible.

Conclusion:
Based on the given information and the calculations, it seems that there is an error in the problem statement. The problem cannot be solved as it stands because the given information does not provide a valid solution.
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Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:a)60 gallonsb)100 gallonsc)120 gallonsd)180 gallonsCorrect answer is option 'C'. Can you explain this answer?
Question Description
Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:a)60 gallonsb)100 gallonsc)120 gallonsd)180 gallonsCorrect answer is option 'C'. Can you explain this answer? for Class 7 2024 is part of Class 7 preparation. The Question and answers have been prepared according to the Class 7 exam syllabus. Information about Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:a)60 gallonsb)100 gallonsc)120 gallonsd)180 gallonsCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 7 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is:a)60 gallonsb)100 gallonsc)120 gallonsd)180 gallonsCorrect answer is option 'C'. Can you explain this answer?.
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