# Thread: Two tanks contain equal amounts of water. They are connected by a pipe and 3000....

1. ## Two tanks contain equal amounts of water. They are connected by a pipe and 3000....

Two tanks contain equal amounts of water. They are connected by a pipe and 3000 litres of water is pumped from one tank to the other. One tank then contains 6 times as much water as the other. How many litres of water did each tank contain originally?

2. What are your thoughts? What have you tried? Please comply with the rules laid out in the Read Before Posting that's stickied at the top of every subforum, and share with us any and all work you've done on this problem, even if you know it's wrong. Thank you.

3. Don't worry found the solution

4. Originally Posted by Beatenberg
Don't worry found the solution
Hey, that's great! Glad to hear it. I hope you'll come back again if you have difficulties in the future.

5. Originally Posted by Denis
Why don't you post your solution?
May help someone else...
I suspect that, by "found", the poster means exactly that. Google the exercise, and you'll "find" many complete worked solutions.

6. Originally Posted by stapel
I suspect that, by "found", the poster means exactly that. Google the exercise, and you'll "find" many complete worked solutions.
If you're correct, that's quite sad that the original poster decided to take the easy way out and not actually learn anything. They may or may not come back here, but I strongly suspect they'll be asking for help when the next problem gets assigned to them, and it's the same concept but with different numbers. I guess it's not my problem, though.

7. Ill have a shot. since OP bailed its some practice for me.

if x = tank 1 and y = tank 2

first equation is x=y

second is

x+3000 = 6(y-3000)
x+3000 = 6y - 18000
x= 6y-21000

insert into first equation

6y-21000 = y
5y = 21000
y = 4200

x and y are both 4200 litres

double check by putting 4200 into equation 2

4200+3000=6(4200-3000)
7200 = 7200

not sure if that was the most efficient way or not.

8. Originally Posted by Bronn
Not sure if that was the most efficient way or not.
Truthfully, efficiency isn't all it's chalked up to be. While it can sometimes be helpful to be fairly quick at solving problems (e.g. on a test), it's far more important to get the right answer, even if it takes you a bit longer. The only tiny thing I'd caution about your work is that instead of plugging the answer you want to check back into one of the equations, you'll want to check if your answer makes sense in the context of the problem text. It's possible your answer checks with the second equation, but it's the wrong equation for the problem. In your case, your answer is that the tanks each started with 4200 liters in them. If 3000 liters is pumped from one tank into the other, the tanks have 1200 and 7200 liters, respectively. 7200 liters is six times as much as 1200 liters, so the answer checks out.

9. Originally Posted by ksdhart2
Truthfully, efficiency isn't all it's chalked up to be. While it can sometimes be helpful to be fairly quick at solving problems (e.g. on a test), it's far more important to get the right answer, even if it takes you a bit longer. The only tiny thing I'd caution about your work is that instead of plugging the answer you want to check back into one of the equations, you'll want to check if your answer makes sense in the context of the problem text. It's possible your answer checks with the second equation, but it's the wrong equation for the problem. In your case, your answer is that the tanks each started with 4200 liters in them. If 3000 liters is pumped from one tank into the other, the tanks have 1200 and 7200 liters, respectively. 7200 liters is six times as much as 1200 liters, so the answer checks out.
yeah. I did have to remind myself what the second equation actually meant when I got the answer 7200. I can see that has potential to be confusing.

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