Logic Problem?

Question

There are 4 jugs. One jug can hold 9litres and is full. The other three are empty and can hold 7, 4, 2 litres. How can I get three litres in three of the jugs?

You have to get exactly 3 litres in three of the jugs and you can't use a measuring device. This is for my daughter's homework so no rude remarks please.

Answer 1

knowing that the 9 litre jug is full, measure out 3 litres in three of the jugs with only the jugs to aid you.

9L-----7L-----4L-----2L
jug 1 jug 2 jug 3 jug 4

5-------0-------4-------0
5-------4-------0-------0
1-------4-------4-------0
1-------7-------1-------0
1-------5-------1-------2
3-------5-------1-------0
3-------3-------1-------2
3-------3-------3-------0

the minimum movemnts of the jugs is eight times

Answer 2

Pour 3 litres into the 7 litre jug and 3 more litres into the 4 liter jug.
3 jugs with 3 liters each.

Answer 3

Pour liquid from the 9 and fill the 4 and 2. Now there is 3 in the 9 container.
Pour the 2 into the 7 and 1 liter from the 4 into the 7 and the 7 has 3 and the 4 has 3.

Answer 4

what about pouring 3 litres in the 7 litre jug, 3 litres in the 4 litre jug and then pouring 6 out of the full 9 litre jug?

Answer 5

pour 3 litres in the 7 litre jug, 3 litres in the 4 litre jug and pour 6 out of the full 9 litre jug ????????

Answer 6

Fill the 4l up to the brim using the 9l and pour this 4l into the 7l jug. Using the 9l jug (with 5l in it), fill up the 4l jug and use this to fill up the 7l jug. Pour the 1l in the 4l jug into the 2l jug. Fill up the 4l jug using the 7l jug. Fill up the 2l jug using the 4l jug (it now has 3l). Pour the contents of the 2l jug into the 9l jug. Problem solved!

Another way of presenting it:
9 0 0 0
5 0 4 0
5 4 0 0
1 4 4 0
1 7 1 0
1 7 0 1
1 3 4 1
1 3 3 2
3 3 3 0

Answer 7

tip 3 litres into the 7 & 3 litres into the 4...you then have 3x3 litre jugs

Answer 8

I am not sure it is minimum number of steps. However it works.
I will use notation x(y) where x is the jug capacity and y is its content in litres. Here are steps:
1. 9(9) 7(0) 4(0) 2(0)
2. 9(3) 7(0) 4(4) 2(2)
3. 9(3) 7(4) 4(0) 2(2)
4. 9(0) 7(4) 4(3) 2(2)
5. 9(0) 7(4) 4(4) 2(1)
6. 9(0) 7(7) 4(1) 2(1)
7. 9(1) 7(7) 4(0) 2(1)
8. 9(1) 7(3) 4(4) 2(1)
9. 9(1) 7(3) 4(3) 2(2)
10. 9(3) 7(3) 4(3) 2(0)

Answer 9

dump all of the 9 into the 7, so you have 2 in the 9, and the 7 is full. then dump all of the 7 into the 4 so the 4 is full and there is 3 in the 7.and im not sure about the rest, but that is what you have to keep doing, trying different combinations.

Answer 10

Fill the seven litre container from the nine litre container (LC for short), fill the four LC with the seven LC leaving three litres in the seven LC.

Put the four ltrs back in the nine LC making six ltrs, put the three in the seven LC into the four LC. Put the six ltrs in the nine LC into the seven LC. Put two of the three litres in the four LC into the two LC leaving one ltr. Put the two back in the nine LC making eight.

Eight remains in the nine litre, put it into the seven LC leaving one ltr, then pour the seven LC into the four LC leaving three in the seven LC. Put the four LC in the nine making five. Put the one ltr in the two LC into the four LC. Fill the two LC with the water in the nine leaving three, put the two ltrs in the two LC into the four making it three ltrs in the nine, seven and four.