Its Seems to be (D) to me.

The Container no. doesn't matter here.

Please post me with the correct ans.

Guys, to get a kudos point you have to provide a solution. Anyone care to try?
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I have a bit of confusion here..
Do we want 4 gallons in each container or 4 gallons in any 1 of the containers..
thanks

IMO D.

Using plugin method:

Statement 1:
For this example I used real numbers to help visualize. Container A is 10 gallons, Container B is two gallons less which will be 8. First fill up Container A to 10 gallons, take Container A's water and fill the Container B to the top leaving 8 gallons in the Container B and 2 gallons in Container A. Take the remaining two gallons from Container A and put it into the Container C. Take the 8 gallons from container B and put it back into container A. Fill container A to the top again. Repeat the process of filling container B to the top (8 gallons) which leaves 2 gallons in container A, pour the remaining 2 gallons into container C, you now have 4 gallons in Container C. This process works with any numbers.

Statement 2: same idea as statement 1, sufficient

At first glance,


If 1) is true:

Fill container one. Then pour out container 1 until container 2 is full. This leaves you with two extra gallons. Pour those two gallons into container 3.

Repeat the process and you have 4 gallons in container 3.

2)Fill container 2. Then pour out container 2 into container 3 until full. This leaves you with two extra gallons. Pour those two gallons into container 1.

Repeat the process and you have 4 gallons in container 1.



But let's think about this. Both of these are predicated on the assumption that the remaining container can hold at least 4 gallons of water. That information is not given in the question itself. so we can't assume that.



Given both 1) and 2), we have something that looks like this: C(1) = C(2) + 2 = C(3) + 2 ----> C(1) = (C3) + 4. So fill container 1, then pour it into 3 until 3 is full. Four gallons wil be remaining.


So you need BOTH.

S1. We have 2 containers differing 2 gallons and third that can have any capacity. The problem is that they are unmarked, so we may have problem with finding exactly those containers differing 2 gallons. INSUFFICIENT

S2. The same problem, so INSUFFICIENT

S1+S2. We have three containers differing one another. Even without marking we can differ low, middle and high capacity containers. So, they can be

1,3,5
0.01, 2.01, 4.01
3,5,7
7,9,11
etc.

Idea is that first we pour all water to the biggest container (it is anyway> 4 gallons), then pour it to smallest and difference will be exactly 4. But to measure it the volume of water should be equal to or more than capacity of biggest container. For example, if capacity 7 gallons and volume of measuered water is 6 gallons, the difference between 3rd and 1st containers will be only 3 and conclusion will be wrong

So, must be E

If this were a usual puzzle, each statement alone would be sufficient but this is a data sufficiency question and you cannot assume anything so here the answer will be (C). Here is why:

Three containers and unlimited water. How will you measure 4 gallons?

(1) The capacity of the first container is 2 gallons more than the capacity of the second container.
Step 1: Fill the first container to brim.
Step 2: Pour its water into second container till it is full.
Step 3: Now leftover water in first container is 2 gallons. You pour this 2 gallons in third container.
Step 4: Empty second container and repeat steps 1 and 2.
You now have 4 gallons, 2 gallons in third container and 2 gallons in first container.
The problem in a data sufficiency question is that you cannot assume that the third container can hold 2 gallons. What if its capacity is only 1 gallon? Where do you put the 2 gallons of water then? This makes statement 1 alone INSUFFICIENT.


(2) The capacity of the second container is 2 gallons more than the capacity of the third container.
This statement alone is exactly like statement 1 alone. Just that the containers are different but the case is exactly the same. This makes statement 2 alone INSUFFICIENT.

Using both, we now know that capacity of first container is 4 gallons more than the capacity of third container. Now all you have to do is fill first container and pour its water in third container till it fills up. Whatever is left in first container is 4 gallons.

Answer (C)
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It might be tempting to think that either statement is sufficient to answer this question. After all, pouring water from the larger container to the smaller container will leave exactly 2 gallons of water in the larger container. Repeating this operation twice will yield 4 gallons of water. The problem is - where would these 4 gallons of water accumulate? We will need to use one of the containers. However, neither statement alone tells us whether one of the containers will hold 4 gallons of water. On the other hand, statements (1) and (2) taken together ensure that the first container can hold at least 4 gallons of water. We know this because (from statement 1) the first container holds 2 gallons
more than the second container, which (from statement 2) holds 2 gallons more than the third container, which must have a capacity greater than 0. Since we know that the first container has a capacity of at least 4 gallons, there are several ways of measuring out this exact amount. One method is as follows: Completely fill the first container with water. Then pour out just enough water from the first container to fill the third container to the brim. Now, 4 gallons of water remain in the first container. Alternatively: Fill the first container to the brim. Pour out just enough water from the first container to fill the second container to the brim. There are now 2 gallons of water in the first container. Now pour water from the second container to fill the third container to the brim. There are now 2 gallons of water in the second container. Finally, pour all the water from the second container into the first container. There are now 4 gallons of water in the first container.

Simple way:

Statement 1 and 2 are insufficient as we don't have information about the third container

Combining we can say
Let X,Y,Z be the three container and let the capacity be a in 3rd container
so
X Y Z
a+4 a+2 a

we can see clearly that the container X if 4 Gallons more than Z so to measure exactly 4, fill container X to full and then use the water in X to fill containder Z the amount left in X will be exactly 4 gallons after filling Z.

Container 1 can hold 2L > Container 2
Container 2 can hold 2L > Container 3

Therefore, Container 1 can hold 4L > Container 3.

Fill up Container 1 fully and then transfer the water to Container 3. You would be left with 4L in container 1.

Therefore, C is the right answer.
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