Henry Ernest Dudeney/Puzzles and Curious Problems/276 - An Effervescent Puzzle

Puzzles and Curious Problems by Henry Ernest Dudeney: $276$

An Effervescent Puzzle

In how many ways can the letters in the word $\text {EFFERVESCES}$ be arranged in a line without two $\text E$s ever appearing together?

Of course, two occurrences of the same letter, such as $\text {F F}$, have no separate identity,

so that to interchange them will make no difference.

When the reader has done that, he should try the case where the letters have to be arranged differently in a circle, with no two $\text E$s together.

We are here, of course, only concerned with their positions on the circumference, and you must always read in a clockwise direction.

Sources

• 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Combination and Group Problems: $276$. -- An Effervescent Puzzle
• 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Combinatorial & Topological Problems: Miscellaneous Combinatorial Puzzles: $459$. An Effervescent Puzzle