Explanation:

Given ratio of initial mixture of milk and water in Q = 5 : 3

Let the initial quantity of mixture in vessel Q = 8x

Let quantity of Milk = 5x and

Let quantity of water = 3x

According to the question,

5x + 10 x 3/5 /3x + 10 x 2/5  = 8/5

= 25x + 30 = 24x + 32

= x = 2

Required Initial quantity of milk = 5x = 5 x 2 = 10 lit.

Hence, option 1 is the correct answer.