A grope of 13 people landed on an alien planet and got stuck on it until help comes they started to gather red and blue fruit. they made two big piles for the blue and red fruit. in the middle of the night a person didn't want trouble in the morning so he split the red fruit equally into 13 piles and the blue fruit equally 13 piles but he had an extra blue fruit so he put it in his pile hides his 2 piles and combines the 13 blue and the 13 red piles into 1 red and 1 blue pile.
A half-hour later another person wakes up to do the same thing but there were 2 extra blue fruits and 1 extra red fruits she decides to put them in her piles.
the 3rd person did the same but now there was 3 extra blue and 2 extra red.
and so on ...
until the 13th person, the captain did a similar did thing had 0 extra blue fruits and 12 extra red fruit. but decides to put each red fruit on top of each person's blue pile beside himself. and woke everyone up to show what he did for them.
the 12 people others felt sadden for hiding it but didn't want to get in trouble so they didn't say anything.
how many blue fruits did they have at the beginning and how many red fruits did they have in the beginning?
It's simply like the monkeys and the coconut problem here's a link to how to solve a problem like this https://www.youtube.com/watch?v=U9qU20VmvaU I think it might help you (: