(Start with problem #1 and see if you can solve all 9)

How would you use 3 jars with the indicated capacities to measure out the desired amount of water? |
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Problem # |
Jar A |
Jar B |
Jar C |
Desired Quarts of water |

1 |
29 |
3 |
. |
20 |

2 |
21 |
127 |
3 |
100 |

3 |
14 |
163 |
25 |
99 |

4 |
18 |
43 |
10 |
5 |

5 |
9 |
42 |
6 |
21 |

6 |
20 |
59 |
4 |
31 |

7 |
23 |
49 |
3 |
20 |

8 |
15 |
39 |
3 |
18 |

9 |
28 |
76 |
3 |
25 |

Were you able to solve all 9? See the discussion below once you have given it a try.

- "
**Persistence of set**" in the water jar problem (Luchins, 1942) - Problems 2 thru 6 can all be solved by filling Jar B, then subtracting Jar A once, then subtracting Jar C twice. This creates a "set" for solving the problems this way.
- Problems 7 and 8 can be solved using the same method as the previous problems, but they could be solved more efficiently by starting with Jar A instead. The "set" for starting with Jar B often prevents people from seeing the simpler solutions.
- Problem 9 can not be solved in the same way as problems 2 thru 6. You must break out of the set to find a solution.