There is a vessel of 3L, 4L, and 7L, and the scale is not attached on each.
Water is in the vessel of 7L full.
How many times as less as possible do you need leaving 5L in 7L vessel by using three vessels ?
Answer
Five times
Solution
1st round :
Transfer 3L out of 7L vessel to 3L vessel.
2nd round :
Transfer 3L of #l vessel to 4L vessel.
3rd round :
Transfer 3L out of 4L in 7L vessel to 3L vessel.
4th round :
Transfer 1L out of 3L vessel to 4L vessel.
There is already 3L in 4L vessel, it is 1L can be transferred.
At this moment there is 1L in 7L vessel, 4L in 4L vessel and 2L in 3L vessel.
5th round :
Transfer 4L out of 4L vessel to 7L vessel.
Then there is 5L in 7L vessel.
