Milk/Water Ratio

[singhsubir]

In a mixture of 120 L, the ratio of milk and water is 2 : 3. If 30 L of mixture is replaced by 18 L of milk and 12 L of water, then new ratio of milk and water is
(A) 3 : 4
(B) 11 : 9
(C) 2 : 3
(D) 7 : 9
(E) 9 : 11

Thanks.

[eagleeye]

Hi Singhsubir:

We have 120L, out of which 30L is removed, hence we are left with 120-30 = 90L,

Now milk in 90L = 2/(2+3) * 90 = 36L then total milk after replacement = 36 + 18 = 54L
Also water in 90L mixture = 3/(2+3) * 90 = 54L, the total water after replacement is 54 + 12 = 66L
Hence the new ratio = milk/water = 54/66 = 9/11 hence the final ratio is 9:11, and answer is E

Let me know if this helps

[GmatKiss]

IMO: E