concentration of acid

[gmatnmein2010]

Xgrams of water were added to the 80 grams of a strong solution of acid. As a result, the concentration of acid in the solution became times of the initial concentration. What was the concentration of acid in the original solution?

1. x=80
2. y=2

[ajith]

Xgrams of water were added to the 80 grams of a strong solution of acid. As a result, the concentration of acid in the solution became times of the initial concentration. What was the concentration of acid in the original solution?

1. x=80
2. y=2

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[thephoenix]

Xgrams of water were added to the 80 grams of a strong solution of acid. As a result, the concentration of acid in the solution became times of the initial concentration. What was the concentration of acid in the original solution?

1. x=80
2. y=2

St1:
80 gms of water is added to 80 gms of acid solution.
So if original acid solution contained x% acid concentration,
then on adding 80 gms of water the concentration will become x/2%.
But we still do not know the value of x. it can be anything
=> NOT SUFFICIENT

St2:
This statement states that the new concentration if 1/2 of the original concentration which means that 80 gms of water has been added.its same as s1)
=> NOT SUFFICIENT


St1 & St2 Together:
Since both the statements give the same piece of information.
=> NOT SUFFICIENT

ANS: E

[shashank.ism]

Xgrams of water were added to the 80 grams of a strong solution of acid. As a result, the concentration of acid in the solution became times of the initial concentration. What was the concentration of acid in the original solution?

1. x=80
2. y=2

from the given problem
Let p grams be the amount of acid present
[(p)/80]y = [p/(80+x)]
(80+x)y= 80
St.1) x=80 --> 160 y = 80 --> y = 1/2 but p can't be calculated
St.2) y=2 =--> (80+x)= 40 x= -40 insufficient
combined also p can't be calculated...
SO E