Harshita6789 wrote:
Starting from a certain mixture of milk and water, 10% mixture was removed and replaced by pure milk. The same process was repeated by successively removing and replacing 20%, 30% and 40% of the mixture with pure milk. If the ratio of milk to water in the final mixture is 68:7 then the initial ratio was
(A) 11:4
(B) 56:25`
(C) 18:7
(D) 16:9
(E) 15:9
We are adding back milk so we need to work with water here.
Initial concentration of water = Ci
Final concentration of water = 7/75
7/75 = Ci * (90/100)*(80/100)*(70/100)*(60/100)
Ci = 10*10*10*10/75*9*8*6 = 25/81
Ratio of milk:water initially = 56:25
Answer (B)
For more, check:
https://www.veritasprep.com/blog/2012/0 ... -mixtures/
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Karishma
Veritas Prep GMAT Instructor
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