One fine day, Santa and banta were playing cards, but suddenly power went off and they were getting bored. So santa randomly inverted position of 10 cards out of 52 cards(and shuffled it) and asked banta to divide the card in two pile with equal number of inverted cards(number of cards in each pile need not be equal). It was very dark in the room and banta could not see the cards, after thinking a bit banta divided the cards in two piles and quite surprisingly on counting number of inverted cards in both the piles were equal.
What do you think banta must have done?
Inverted cards puzzle solution
I would recommend to think again before reading the solution.
If tried enough, here it is:-
Just take top 10 cards from the pile and reverse them, now you will two piles of 10 cards and 42 cards and both of them will have same number of inverted cards.
Inverted cards puzzle explanation
lets say there were n inverted cards initially in top 10 cards, obviously in remaining 42 cards number of inverted cards will be 10 -n, as total 10 inverted cards.
Now on reversing the 10 cards number of inverted cards would become 10 – n. thus number of inverted cards will become same in the two piles.