Math Word Problem

Question

given only 2 irregular shaped jars that will hold 7 quarts and 3 quarts of water,describe a sequence of filling and emptyings that willpermit you to come back from the brook with exactly 5 quatrts of water

Answer 1

If you take your two empty jars and first fill up the 7 quart one.  Pour that into the 3 quart one, which gives you 4 quarts left.

 

Then empty the 3 quart one, and fill it again with the water from the 7 quart one, this time it'll leave 1 quart behind.

 

Now put that 1 quart of water into the 3 quart jar.

 

Fill up the 7 quart jar again and pour it into the 3 quart jar, but this time you can only fit 2 quarts of water in it because it already had 1 quart in it.

 

What you'll have left is 5 quarts of water in the 7 quart jar.

Answer 2

Since these quarts are irregular, you are sure of the volume only when you completely fill them.

 

1. Take both containers to the brook.

 

2. Fill the 7-jar with water.

 

3. Empty it into the 3-jar.  There is 4 quarts in the 7-jar.

 

4. Empty the 3-jar and fill it with 3 quarts from the 7-jar.  1 quart remains in the 7 jar.

 

5. Empty the 3-jar.

 

6. Pour the 1 quart from the 7-jar into the 3-jar.  The 7-jar is now empty.

 

7.  Fill the 7-jar to get 7 quarts.

 

8.  Fill the 3-jar with 2 quarts to fill it.

 

9.  The 7-jar now has 5 quarts.