Question

How can you measure 6 liters of water using only 4 and 9-liter bowls?

Answer 1

Let us suppose we have full 9 liter bowls then somnthink like this can be done:-

0,  9
4,  5
0,  5  (after removing 4 liter bowl to somwhere else.)
1,  4
1,  0 (after removing 4 liter bowl to somwhere else.)
1,  9 (after filling the 9 ltr bowl again.)
4,  6 (after pouring 3 ltr in 4 ltr bowl.)