The minimum quantity of milk in litres (in whole number) that should be mixed in a mixture of 60 litres in which the initial ratio of milk to water is 1 : 4 so that the resulting mixture has 15% milk is
This is not possible
Total mixture = 60L
Milk: Water = 1: 4
Milk = 1/5 x 100 => 20%
and after adding only milk, the quantity of milk is becoming 15% which is not technically correct.
Because after adding a particular fluid, that's quantity should get increased.