The numbers less than 696 and are squares of certain numbers are 676, 625.The least number that should be subtracted from 696 to make it perfect square = 696 - 676 = 20.
Original mixture = 5 litre; Milk = 3.5 litre;Water = 1.5 litre Let x litre of milk be added so thatthe mixture becomes (x + 5) litres and the percentage of water becomes 5%So, 1.5 = (x + 5) x 5/10030 = x + 5∴ x = 25 litre