The Water Jug Challenge : Puzzle

You've got a 4 liter jug and a 9 liter jug. 

You've got a pool of water. 

What is the fewest number of steps it takes to come up with exactly 6 liters of water? 

No, you cannot pour some water into the 9 liter jug and then guess. Nor can you fill each jug up half way or something. You have to be exact. A step is defined as putting water into a jug (not emptying). For instance, filling the 4 liter jug and then pouring it into the 9 liter jug is 2 steps.

Click here for SOLUTION! 

The Water Jug Challenge Puzzle : Solution

What was the puzzle?

We've got a 4 liter jug and a 9 liter jug. 

We've got a pool of water. 

We have to find fewest number of steps it takes to come up with exactly 6 liters of water. 

STEPS : 

1. Fill up the 9 liter jug from the pool.         9L - 9  4L - 0

2. Fill up the 4 liter jug from the 9 liter jug. 9L - 5  4L - 4

3. Empty the 4 liter jug into the pool.          9L - 5  4L - 0

4. Fill 4 liter jug again from the 9 liter jug.   9L - 1  4L - 4

5. Empty the 4 liter jug into the pool           9L - 1  4L - 0

6. Transfer 1 liter left 9L jug into the 4L.     9L - 0  4L - 1

7. Fill the 9 liter jug from the pool.             9L - 9  4L - 1

8. Fill up the 4 liter jug from the 9 liter jug. 9L - 6  4L - 4

That's how we have exactly 6 liters of water in 9 liters jug. 

Make it 50-50 in Two!

You have three jugs:

A 10-liter jug, filled with water
A 7-liter jug, empty
A 3-liter jug, empty

Your objective is to end up having 5 liters of water in the 10-liter jug, and 5 liters of water in the 7-liter jug.

Note that you have nothing else at your disposal other than these three jugs and that you cannot perform measurements by eye or based on the shape of the jugs.

THIS is how it can be done! 

Making it 50-50 in Two!

What was the challenge?

Let us label the 10-liter jug as A, the 7-liters jug as B, and the 3-liters jug as C.

 
STEPS : 

1]  Pour Jug A into Jug C.      A : 7    B : 0    C : 3
 
2]  Pour Jug C into Jug B.      A : 7    B : 3    C : 0

3]  Pour Jug A into Jug C.      A : 4    B : 3    C : 3

4]  Pour Jug C into Jug B.      A : 4    B : 6    C : 0

5]  Pour Jug A into Jug C.      A : 1    B : 6    C : 3

6]  Pour Jug C into Jug B.      A : 1    B : 7    C : 2

7]  Pour Jug B into Jug A.      A : 8    B : 0    C : 2

8]  Pour Jug C into Jug B.      A : 8    B : 2    C : 0

9]  Pour Jug A into Jug C.      A : 5    B : 2    C : 3

10] Pour Jug C into Jug B.     A : 5    B : 5    C : 0

Task Completed.