by Andrew Skidmore
After removing an even number of red cards from a standard 52 card pack, I shuffled those that remained and split them into two piles.
A randomly chosen card from the first pile was black. After shuffling this card into it, a randomly chosen card from the second pile was red.
It turned out that the probability of these two results was the same whole number percentage.
How many cards had I initially removed from the pack?