**There are 6 keys and 6 locks. At most how many tries are required before it is certain that each lock has found its key?**

**Which answer is correct?**

**One answer is as follows: 6 x 6=36 tries ( Is this correct?)**

**The other answer is as this:**

** Use the 6 keys to try 1 lock at a time and at most 5 tries are required before the lock finds its key. Move the key and lock away from the groups. Now there are 5 locks and 5 keys left. **
** Use the 5 keys to try another lock and at most 4 tries are required before the lock finds its key. Move the second set of key and lock out of the groups. Now there are 4 locks and 4 keys left. **
** Use 4 keys to try another lock and at most 3 tries are required before the lock finds its key. Move the third set of key and lock out of the groups. Now there are only 3 locks and 3 keys left. **
** Use the 3 keys to try another lock and at most 2 tries are required before the lock finds its key. Now more the fourth set of key and lock out of the groups. Now there are only 2 locks and 2 keys left. **
** Use the 2 keys to try one of the remaining locks and at most 1 try is required for the lock to find its key. Move the 5th set of key and lock out of the groups. Now there are only 1 key and one lock left and they should be one set. **

**How many tries are there from the above steps?**

**5+4+3+2+1=15 tries**

**Of course, the second answer is correct. When you see a verbal problem, do not rush to get the answer. Always think it through. **

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