Ok, I was confused to choose whether it’s “Informatics” or “Computer Science”. I read many sources, asked many people, but nothing come in conclusion. So I just write both for the title. However, since the faculty I am currently working in is called “Informatics”, let’s use that in the post. So, it’s me, a lecturer…

There are 13 blue balls and 15 red balls in a box. Outside the box, there also 28 red balls. Remove two balls randomly from the box. If they have different colours then put the blue one back to the box. If they have the same colour, take them out and put a red ball in…

There is a woman who just passed away and was asked to choose one between two available doors. One door is a door to heaven, and another one is a door to hell. Each door has one guard. The guard of heaven always tell truth, and the guard of hell always tell lies. She was…

One day, I asked Andy when is his birthday. Instead of giving me a date, he replied: “Two days ago I was 25 years old, and next year I will be 28.” Then, I know when his birthday is.   How can?       Solution → (better not open this if you don’t have…

(yes, it’s been everywhere on the internet… I just love the traps in this question so I re-write it here)   Albert and Bernard just become friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates: May 15, May 16, May 19, June 17,…