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Solutions for Session 3, Part A
See solutions for Problems: A1 | A2 | A3
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Problem A1 | |
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The inputs 12 and 8 each lead to the output 4. If you only knew that the output was 4, it would be impossible to determine which of 12 and 8 was the correct input.
<< back to Problem A1
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Problem A2 | |
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Some examples:
• | Driving directions. Telling someone how to get somewhere usually allows them to figure out how to get back (if there are no one-way streets involved). In particular, to drive back you must take each road the opposite direction, and in reverse order (last road first). |
• | Packing and unpacking. Especially with commercially shipped packages, it can be difficult to re-pack a box without knowing where things were located before you unpacked it. |
• | In mathematics, many algebra problems involve "undoing" steps. For example, if 3x = 12, you can find x by undoing the multiplication step. |
<< back to Problem A2
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Problem A3 | |
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Lots of things can't be undone easily, like throwing a water balloon, using gasoline in a car engine, or exploding fireworks.
<< back to Problem A3
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