Member for 3 years, 5 months
Last seen more than a month ago
Yevpatoria, Republic of Crimea, Russia
If the double factorial is allowed, then I propose WolframAlpha agrees that the result is 19.
Using the notation of double factorial: WolframAlpha approves it.
For Puzzle #1, I'll go with this math style approach For Puzzle #2 and Puzzle #3, my answers would be exactly the same with Dr. Roggia's and Ian Fako's answers.
Some users here might find this answer sexist, but unfortunately, it is true. So, my guess is