Question

2) there are two mugs one with 4 litres and the other with 5 litres capacity. How will you pour exactly 7 litres of water?

Answer 1

first fill the 4L mug and pour it in the 5L mug. Again fill the 4L mug and pour it into 5L mug .Only 1L would fit in the 5L mug. Now the 4L mug will have 3L of water in it. Now transfer this 3L into another mug and fill the 4L mug.

Adding these (3+4) = 7L

Hope it helps... :)