TIME consuming

[vishubn]

If Pool Y currently contains more water than Pool X, and if Pool X is currently filled to 2/7 of its capacity, what percent of the water currently in Pool Y needs to be transferred to Pool X if Pool X and Pool Y are to have equal volumes of water?

(1) If all the water currently in Pool Y were transferred to Pool X, Pool X would be filled to 6/7 of its capacity.

(2) Pool X has a capacity of 14,000 gallons.

it toookk way too long

shortcuts??

[mals24]

IMO A

Let the capacity of Pool X = X

Pool X = 2/7X filled.
To solve the question we just need to know the quantity of water in pool Y.

St1:

(1) If all the water currently in Pool Y were transferred to Pool X, Pool X would be filled to 6/7 of its capacity.

So after transferring the water from Y to X, quantity of water in pool X = 6/7
6/7-2/7 = 4/7, which is the quantity of water in pool Y.

So SUFF.

St2:

(2) Pool X has a capacity of 14,000 gallons.

We cant deduce anything about Pool Y from this information. INSUFF

So A.

[vittalgmat]

Thanks Mals,
that was elegent. Couldnt have thought a faster one.

[ronniecoleman]

The only shortcut i think can be use of word percentage...

Since percentage is required generally options with concrete answers are out of scope.. ( i mean generally)

Now it is said that

Capacity of A is greater than B

B = 2/7 X

Now If we add all A to B it becomes 6/7 x

so A has 4/7x

now

Midpoint of 2 and 6 is 4

So Final volume will be 4/7 x in both the containers