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I wanted to write that, in theory, it's possible to have non-twins with a small age difference (less than a year). And in general, the fact that the wife was alone all the time is not mentioned in the problem.
The magician took a deck of cards (52 cards), face down, counted out 20 cards, turned them face up, and handed them to the spectator. The spectator mixed the face-up cards with the entire deck and thoroughly shuffled the deck so that the face-up cards were randomly distributed within it. Then, holding the deck under the table so that the cards were not visible, he counted out 20 cards from the top and handed them to the magician.
The magician, taking the stack and still holding it under the table, says: "Now I will try to equalize the number of face-up cards in my part of the deck and in yours by touch. To do this, I need to turn over a few more cards." Then, after some manipulations, still under the table, he takes out his cards, lays them out on the table, and counts the face-up cards. There are exactly as many as there are among the 32 cards of the spectator.
What is the secret of this trick?
Added 4 minutes later
Let's say there are 5 face-up cards left in the spectator's deck, and the magician or the person under the table counted 15 face-up cards in his deck. This means that 10 face-up cards need to be turned back face down.
If, for example, there are 15 face-up cards left with the spectator, then the magician or assistant will count 5 in his deck, and another 10 face-down cards will need to be turned face up.
Всё не так плохо как Вы думаете. Всё намного хуже!