Henry Ernest Dudeney/Puzzles and Curious Problems/140 - A Curious Progression/Solution
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Puzzles and Curious Problems by Henry Ernest Dudeney: $140$
- A Curious Progression
- A correspondent sent this:
- "An arithmetical progression is $10, 20, 30, 40, 50$, the five terms of which sum is $150$.
- Find another progression of five terms, without fractions, which sum to $153$."
Solution
The solution given by Dudeney's correspondent, which is as good a solution as any, is:
- $153 = 1! + 2! + 3! + 4! + 5!$
where $n!$ denotes the factorial of $n$.
We at $\mathsf{Pr} \infty \mathsf{fWiki}$ came to the same conclusion by clicking on 153, on which this fact is presented.
Also see
Sources
- 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Solutions: $140$. -- A Curious Progression