|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
07 Feb 2014, 03:26
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
79% (01:46) correct
21%
(02:00)
wrong
based on 317
sessions
History
Date
Time
Result
Not Attempted Yet
What strength of 20 ml alcohol should be added to 10ml of 50% alcohol to get an average strength of 20% alcohol.
A. 0.5 %
B. 5 %
C. 50 %
D. 5.5 %
E. 0.05 %
A. 0.5 %
B. 5 %
C. 50 %
D. 5.5 %
E. 0.05 %
14 Dec 2014, 05:53
Kudos
Bookmarks
Table notation
-----------------------Alcohol--------Water----------Total
Original solution-------5---------------5--------------10
Adding solution--------x---------------y--------------20
Final solution ----------6--------------24-------------30
so, x=6-5=1, y=24-5=19
(1/20)*100=5%
Differential method
x%-------20%--------50%
20-x/50-20=1/2
10=2x
x=5%
Weighted average
(0.5*10)+(x*20)/30=20/100=1/5
5+20x/30=1/5
100x=5
x=5/100=5%
B
-----------------------Alcohol--------Water----------Total
Original solution-------5---------------5--------------10
Adding solution--------x---------------y--------------20
Final solution ----------6--------------24-------------30
so, x=6-5=1, y=24-5=19
(1/20)*100=5%
Differential method
x%-------20%--------50%
20-x/50-20=1/2
10=2x
x=5%
Weighted average
(0.5*10)+(x*20)/30=20/100=1/5
5+20x/30=1/5
100x=5
x=5/100=5%
B
