BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

X grams

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

X grams

by BTGmoderatorDC » Wed Sep 13, 2017 2:13 pm
X grams of water were added to 80 grams of a strong solution of acid. If as a result, the concentration of acid in the solution became 1/Y times of the initial concentration, what was the concentration of acid in the original solution?


(1) X = 80

(2) Y = 2

What is the best way to determine on which of the 2 statements are the correct answer?

OA E
Top
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

by Jay@ManhattanReview » Fri Sep 15, 2017 1:10 am
lheiannie07 wrote:X grams of water were added to 80 grams of a strong solution of acid. If as a result, the concentration of acid in the solution became 1/Y times of the initial concentration, what was the concentration of acid in the original solution?

(1) X = 80
(2) Y = 2

What is the best way to determine on which of the 2 statements are the correct answer?

OA E
Say out of 80 grams, the original solution had p grams of acid, thus, the original concentration of acid = p/80.

After the addition of x grams of water, the new concentration of acid = p/(80 + x)

We are given that

New concentration = 1/y * Original concentration

=> p/(80+x) = p/80y

y = 80/(80+x); 'p' cancels

The above equation suggests that even if we get the values of x and y, we cannot get the value of p/80, thus none of the statements are sufficient.

The correct answer: E

Hope this helps!

Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide

-Jay
_________________
Manhattan Review GMAT Prep

Locations: New York | Jakarta | Nanjing | Berlin | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.
Top
Post new topic Post Reply
• Page 1 of 1