buoyant wrote:If 12 ounces of a strong vinegar solution are diluted with 50 ounces of water to form a three-percent vinegar solution, what was the concentration of the original solution?
A) 19.3%
B) 17%
C) 16.67%
D) 15.5%
E) 12.5%
[spoiler]OA: D[/spoiler]
When 50 ounces of water is added to the 12 ounces of original solution, we get
62 ounces of a NEW solution.
The new solution is 3% vinegar.
3% of
62 =
1.86
So, the NEW solution contains
1.86 ounces of pure vinegar.
These
1.86 ounces of pure vinegar came from the ORIGINAL solution.
The ORIGINAL solution had a volume of
12 ounces.
1.86 ounces was pure vinegar.
1.86/
12 = what percent?
Well, 1.8/12 = 15%, so
1.86/
12 must be a little bit more than 15%.
Take
D
For more on this shortcut for converting fractions to percents, see my article: https://www.gmatprepnow.com/articles/sho ... s-percents
Cheers,
Brent
