One man adds 3 liters of water to 12 liters of milk and another 4 liters of water to 10 liters of milk. What is the ratio of the strengths of milk in 2 mixtures?	Choose the most appropriate option
A) 11 : 21
B) 15 : 33
C) 28 : 25
D) 3 : 2
E) 31 : 33

Rationale: "strength of milk in the mixture = quantity of milk / total quantity of mixture strength of milk in the 1 st mixture = 12 / 15 strength of the milk 2 nd mixture = 10 / 14 the ratio of their strengths = 12 / 15 : 10 / 14 = 28 : 25 answer is c"
Answer: C