Earlier quoted context omitted.
One of the reviews says to look at the sample, but it looks like the sample isn't available any more. Might just be a regional thing that the sample isn't available but maybe they removed it intentionally lol
The first puzzle from the sample: > A seller has some quantity of floor with him. The seller offered his customer that if he/she buys half of the floor he has, he will give half kg of floor as a discount. The first customer accepted his offer and he purchased half of the floor and got half kg as extra. After selling the floor to the first customer he again makes the same offer for the second customer, and so on. The…
I'm not certain of the analogy, but it appears to be something like the white balls are even and the black are odd. Both odd+odd and even+even equal an even (white) number. But odd + even equal an odd number. Since it starts with an odd number of odd numbers, the answer is black.