rakeshd347 wrote:Rodrick mixes a martini that has a volume of 'n' ounces having 40% Vermouth and 60% Gin by volume. He wants to change it so that the martini is 25% Vermouth by volume. How many ounces of Gin must he add?
A) n/6
B) n/3
C) 3n/5
D) 5n/6
E) 8n/5
OA is C
Let V = vermouth and G = gin.
Original solution:
V:G = 40:60 = 2:3.
Let V = 2 ounces and G = 3 ounces.
Thus, n = 2+3 = 5 ounces.
New solution:
After more gin is added, the amount of vermouth -- 2 ounces -- must be 1/4 of the new volume.
Since 2 is 1/4 of 8, the new volume must be 8 ounces.
Thus, the amount of added gin = new volume - old volume = 8-5 = 3 ounces. This is our target.
Now plug n=5 into the answers to see which yields our target of 3.
Only
C works:
3n/5 = (3*5)/5 = 3.
The correct answer is
C.
Last edited by GMATGuruNY on Mon Oct 07, 2013 5:15 am, edited 1 time in total.
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