A milkman had water and milk mixture in a can with water to milk ratio 5:7. He accidently spills 9 liters of the mixture. He then fills the can with water equal in quantity to spilled mixture. This makes the water to milk ratio 9:7. How much milk did the can initially have?
Answer: A
Here milk : water = 7:5
That means quality of milk be 7 or
multiple 7
Only option A i.e. 21 is multiple of 7.
You can check by putting 21 as quantity of milk