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**How many 4-letter “words” may be formed form the letters
PEEPS? For example PEEP, PPEE, SPPE,
etc.**

**[Problem submitted by Don Hentschel, LACC Assistant
Professor of Mathematics.]**

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**Solution 1:**

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**There are three non-overlapping
possibilities: **

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**Case I: two P’s, one E, one S. This has _{} or 12 words.**

**Case II: one P, two E’s, one S. This has _{} or 12 words.**

**Case III: two P’s, two E, no S. This has _{} or 6 words.**

**Total = 12 + 12 + 6 = 30**

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**Solution 2:**

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**There are _{} ways to arrange all
letters if no two were the same; dividing by repetitions: 2! and 2! we have
120/4 = 30.**

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**Solution 3: **

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** An
organized student may list them, there are only 30.**