hottestlegs:

Let me be clearer here. using the calculated flow rate above. flow rates: A=5l/m, B=3.33l/m, C=6.6l/m
for first minute only A contributes: 5liter; in the second mins, A & B contributes 5litres and 3.33liters respectively totaling 8.33liters
total liters contributed in the 1st and 2and minutes=13.33liters____ this implies that for the first two minutes 13.33liters of the tank is filled
remaining volume of tank to be fill=100-13.33= 86.67liters
3rd minute and above A, B & C contribute with a total flow rate of 15liters/min to fill 86.67liters and this will take 86.67/15=5.778min
hence the total time required=5.778+2=7.78mins

Three pipes A, B & C empties into a tank. A can fill it in 20mins, B in 30mins, C in 15. If the three pipes were switched on in one successive minutes, how long does it take them to fill the tank?
Modification.
Plz note, one successive minutes ere actually mean one minute after the oda.A @ 0mins, B 1mins aftr, C 1mins aftr B.
Efforts of all contribitors are well commended.

shinebabe:

You are assuming that "successive" in the ops question means that each pipe will be left open when opening the next pipe. There isn't enough info to make this definitive.

Three pipes A, B & C empties into a tank. A can fill it in 20mins, B in 30mins, C in 15. If the three pipes were switched on in one successive minutes, how long does it take them to fill the tank?
Modification.
Plz note, one successive minutes ere actually mean one minute after the oda.A @ 0mins, B 1mins aftr, C 1mins aftr B.
Efforts of all contribitors are well commended.
SOLUTION

Wait. Answer is 6.667 minutes. Wait for explanation. Let the capacity of the tank be X. Then the Pipes have flow rates of x/30, x/20 and x/15 per minute respectively. So the total flow rate all working together would be x/30+x/20+x/15=3x/20 lets say litres per minute. Now the time for the 3 would be capacity divided by flow rate = X divided by 3x/20= 20/3=6.667 minutes. CLAP FOR ME!

chai

Your question is meant to read "how many minutes will be required to fill the tank if all pipes were switched on at the same time?"

The answer is 6.66 minutes. I will explain it:

Let the tank size x be assumed to be 100 liters.

If Pipe A can fill it in 20 minutes, pipe A pumps 5 liters per minute (100/20)
If Pipe B can fill it in 30 minutes, it then pumps 3.33 liters per minute (100/30min)
If Pipe C can fill it in 15 mins, then it pumps 6.6 liters per minute (100/15)

When all pipes are switched on together, they jointly pump about 15 liters per minute (5+3.33+6.6 liters).

Therefore, to fill 100 liter tank, 6.6666 approx. 6.76 minutes will be needed (100/15 liter per minute).

NB: Irrespective of the figure used for the tank capacity, the same result/answer will be achieved. The reason being that you will eventually divide the tank capacity assumed (30, 50, 100 or whatever figure) by what can be jointly pumped by the pipes in one minute (which varies according to capacity assumed).

Where is my prize OP?

ALVA001:
Three pipes A, B & C empties into a tank. A can fill it in 20mins, B in 30mins, C in 15. If the three pipes were switched on in one successive minutes, how long does it take them to fill the tank?

The maths should be elementary enough but the language is wack. What does "one successive minutes" mean?

10mins

Curlieweed:


The maths should be elementary enough but the language is wack. What does "one successive minutes" mean?

I guess its a code for "at once"

Curlieweed:


The maths should be elementary enough but the language is wack. What does "one successive minutes" mean?

lol. Forget the English, solve the massssss

hahn:
10mins

stop guessing

one successive minutes?

dialfa:


stop guessing

I know I got it right.

Answer my own question then if you're such a whiz. Many people came from the north, many from the south, many from the east and many from the west and they all assembled in the middle.

How many people are there?

PassingShot:
Your question is meant to read "how many minutes will be required to fill the tank if all pipes were switched on at the same time?"

The answer is 6.76 minutes. I will explain it:

Let the tank size x be assumed to be 100 liters.

If Pipe A can fill it in 20 minutes, pipe A pumps 5 liters per minute (100/20)
If Pipe B can fill it in 30 minutes, it then pumps 3.33 liters per minute (100/30min)
If Pipe C can fill it in 15 mins, then it pumps 6.6 liters per minute (100/15)

When all pipes are switched on together, they jointly pump about 15 liters per minute (5+3.33+6.6 liters).

Therefore, to fill 100 liter tank, 6.6666 approx. 6.76 minutes will be needed (100/15 liter per minute).

You are assuming the size of the tank to be 100liters. The op didn't state that it is 100liters so you're wrong.

The correct answer is 10mins

PassingShot:
Your question is meant to read "how many minutes will be required to fill the tank if all pipes were switched on at the same time?"

The answer is 6.76 minutes. I will explain it:

Let the tank size x be assumed to be 100 liters.

If Pipe A can fill it in 20 minutes, pipe A pumps 5 liters per minute (100/20)
If Pipe B can fill it in 30 minutes, it then pumps 3.33 liters per minute (100/30min)
If Pipe C can fill it in 15 mins, then it pumps 6.6 liters per minute (100/15)

When all pipes are switched on together, they jointly pump about 15 liters per minute (5+3.33+6.6 liters).

Therefore, to fill 100 liter tank, 6.6666 approx. 6.76 minutes will be needed (100/15 liter per minute).

NB: Irrespective of the figure used for the tank capacity, the same result/answer will be achieved.

You're wrong to assume any figure for the capacity of the tank. Just use X.

hahn:


You are assuming the size of the tank to be 100liters. The op didn't state that it is 100liters so you're wrong.

The correct answer is 10mins

Assume whatever figure for the tank size, you will get the same answer. I have done it with two different figures.

Curlieweed:


The maths should be elementary enough but the language is wack. What does "one successive minutes" mean?

hahn:

I guess its a code for "at once"

ionsman:
one successive minutes?

i think it means that pipe A opens for 1 minute then pipe B for 1 minute and then pipe C, then back to pipe A again etc

ddippset:
You're wrong to assume any figure for the capacity of the tank. Just use X.

How can I be wrong when the answer is correct?

Use whatever figure (30, 50 or 100) and you will arrive at the same answer.

I deliberately avoided using "X" so as not to confuse some people. Btw, why must I use X or Y to solve the problem?

ddippset:
Wait. Answer is 6.667 minutes. Wait for explanation. Let the capacity of the tank be X. Then the Pipes have flow rates of x/30, x/20 and x/15 per minute respectively. So the total flow rate all working together would be x/30+x/20+x/15=3x/20 lets say litres per minute. Now the time for the 3 would be capacity divided by flow rate = X divided by 3x/20= 20/3=6.667 minutes. CLAP FOR ME!

Ambiguous!

PassingShot:

Assume whatever figure for the tank size, you will get the same answer. I have done it with two different figures.

I guessed twice and it's still 10mins. You're wrong

PassingShot:

How can I be wrong when the answer is correct?

Use whatever figure (30, 50 or 100) and you will arrive at the same answer.

I deliberately avoided using "X" so as not to confuse some people. Btw, why must I use X or Y to solve the problem?

I agree with you. Any number you use would give you the same answer, the correct answer. Using your method, I would have opted for the lcm of 20, 30, and 15. Which is 60. I would have used 60 in place of 100 in order to get whole numbers for my calculation. Trust me an examiner would give you 9/10 for assuming a number instead of working with an unKnown X or y or p.

hahn:


I guessed twice and it's still 10mins. You're wrong

If I hear, hahn!

PassingShot:

Ambiguous!

there's nothing ambiguous there. Except for one who isnt grounded in algebraic word problems. A qualified examiner would score me 10/10 and score you 9/10.

PassingShot:

Ambiguous!

You see! I told you we are right. The answer is 6.667mins

Calculating... Wow!... this simple problem almost got me crazy here in the office.


Answer is 7.778 mins

If all pipes are opened at the same time, the tank fills in 6.667 mins, but when 'B' is opened 1 minute after 'A', and 'C' is opened 1 minute after 'B', then the tank fills in 7.778 mins

Assuming:
Tank capacity = T

Flowrate of pipe A = T/20
Flowrate of pipe B = T/30
Flowrate of pipe C = T/15

Total time used in filling tank = t (mins)
Pipe A runtime = t
Pipe B runtime = t-1
Pipe C runtime = t-2

Tank capacity = (Total Flowrate) * (Total time)

T = (T/20)t + (T/30)(t-1) + (T/15)(t-2)
T = (Tt/20) + (Tt/30 - T/30) + (Tt/15 - 2T/15)
After some voodoo on the above equation....
70T = 9Tt
70 = 9t
t = 7.778 mins

ddippset:
Wait. Answer is 6.667 minutes. Wait for explanation. Let the capacity of the tank be X. Then the Pipes have flow rates of x/30, x/20 and x/15 per minute respectively. So the total flow rate all working together would be x/30+x/20+x/15=3x/20 lets say litres per minute. Now the time for the 3 would be capacity divided by flow rate = X divided by 3x/20= 20/3=6.667 minutes. CLAP FOR ME!

PassingShot:
Your question is meant to read "how many minutes will be required to fill the tank if all pipes were switched on at the same time?"

The answer is 6.66 minutes. I will explain it:

Let the tank size x be assumed to be 100 liters.

If Pipe A can fill it in 20 minutes, pipe A pumps 5 liters per minute (100/20)
If Pipe B can fill it in 30 minutes, it then pumps 3.33 liters per minute (100/30min)
If Pipe C can fill it in 15 mins, then it pumps 6.6 liters per minute (100/15)

When all pipes are switched on together, they jointly pump about 15 liters per minute (5+3.33+6.6 liters).

Therefore, to fill 100 liter tank, 6.6666 approx. 6.76 minutes will be needed (100/15 liter per minute).

NB: Irrespective of the figure used for the tank capacity, the same result/answer will be achieved. The reason being that you will eventually divide the tank capacity assumed (30, 50, 100 or whatever figure) by what can be jointly pumped by the pipes in one minute (which varies according to capacity assumed).

Where is my prize OP?

You smart asses obviously missed where the question said "in one successive minutes"

ddippset:
there's nothing ambiguous there. Except for one who isnt grounded in algebraic word problems. A qualified examiner would score me 10/10 and score you 9/10.

And score me 11/10

hahn:

And score me 11/10

lol

PassingShot:
Your question is meant to read "how many minutes will be required to fill the tank if all pipes were switched on at the same time?"

The answer is 6.66 minutes. I will explain it:

Let the tank size x be assumed to be 100 liters.

If Pipe A can fill it in 20 minutes, pipe A pumps 5 liters per minute (100/20)
If Pipe B can fill it in 30 minutes, it then pumps 3.33 liters per minute (100/30min)
If Pipe C can fill it in 15 mins, then it pumps 6.6 liters per minute (100/15)

When all pipes are switched on together, they jointly pump about 15 liters per minute (5+3.33+6.6 liters).

Therefore, to fill 100 liter tank, 6.6666 approx. 6.76 minutes will be needed (100/15 liter per minute).

NB: Irrespective of the figure used for the tank capacity, the same result/answer will be achieved. The reason being that you will eventually divide the tank capacity assumed (30, 50, 100 or whatever figure) by what can be jointly pumped by the pipes in one minute (which varies according to capacity assumed).

Where is my prize OP?

you are nearly there if not for the statement 'one successive minutes. the answer is actually: for 2min A & B contributes 13.3mins hence the remaining volums is 1oo-13.3= 86.7; hence it will take A, B & C 86.7/15 =5.78min; therefore total min: 2+5.78= 7.78min

The answer is approx. 6.67mins.

@passingshot. You are actually wrong about the pipes opening together or at the same time. The op us correct by saying the pipes were opened successively. This us because, practically, when you open all the pipes, flow rate generally reduces when compared to the flow rates taken from each of the pipes. What these flow rates reduce to may not be easily determined and would complicate the calculations here.

This is my core area, so I should know...

hottestlegs:


you are nearly there if not for the statement 'one successive minutes. the answer is actually: for 2min A & B contributes 13.3mins hence the remaining volums is 1oo-13.3= 86.7; hence it will take A, B & C 86.7/15 =5.78min; therefore total min: 2+5.78= 7.78min

This is wrong.

shinebabe:
The answer is approx. 6.67mins.

@passingshot. You are actually wrong about the pipes opening together or at the same time. The op us correct by saying the pipes were opened successively. This us because, practically, when you open all the pipes, flow rate generally reduces when compared to the flow rates taken from each of the pipes. What these flow rates reduce to may not be easily determined and would complicate the calculations here.

This is my core area, so I should know...

For exam purpose, we have to simply find out the pump rate per pipe and do just as I did.
Employing your argument which may be valid in real life, then it is save to say there won't be an answer to the question.
Modified*
Got your point now.

shinebabe:
The answer is approx. 6.67mins.

@passingshot. You are actually wrong about the pipes opening together or at the same time. The op us correct by saying the pipes were opened successively. This us because, practically, when you open all the pipes, flow rate generally reduces when compared to the flow rates taken from each of the pipes. What these flow rates reduce to may not be easily determined and would complicate the calculations here.

This is my core area, so I should know...

wow! happy that a fellow lady is doing this with me. actually sis the flow rate of the individual pipes are not affected in any way by the 'successive minutes' statement only imply that pipe A is ON for a minute before pipe B and then pipe C. this arrangement can only increase the time it takes to fill the tank than when they are all on simultaneously

PassingShot:

For exam purpose, we have to simply find out the pump rate per pipe and do just as I did.
Employing your argument which may be valid in real life, then it is save to say there won't be an answer to the question.

sir, you are actually right going by your approach if the pipe are all ON simultaneously. had you factored the 'successive statement' then you would have been 100%. what I did was factoring the 'successive statement' using your calculated flow rates.

hottestlegs:


sir, you are actually right going by your approach if the pipe are all ON simultaneously. had you factored the 'successive statement' then you would have been 100%. what I did was factoring the 'successive statement' using your calculated flow rates.

I actually thought the "successive" stmt was an error. Good to find out the result is same whether pipes turned on successively after the other or all turned on at once.
Thanks.