7 people had the following conversation.

A: The day after tomorrow is Wednesday.
B: No, today is Wednesday.
C: Both of you are wrong, Wednesday is tomorrow.
D: Today is neither Monday, nor Tuesday, nor Wednesday.
E: I am pretty sure that Thursday was yesterday.
F: No, yesterday was Tuesday.
G: All I know, is yesterday wasn’t Saturday.

Only one of them is telling the truth. On which day did the argument took place?

There are 25 horses and you need to figure out the 3 fastest horses by placing them into races. You can race 5 horses at a time. Each horse always finishes the race in the same amount of time and there are no ties. The only information you get from each race is the order that the 5 horses finished in. You will not get any information regarding the time taken for the horses to complete the race.

What is the smallest number of races you need to find the 3 fastest horses in order?

Imagine there are 3 coins on the table: gold, silver, and copper. If you make a truthful statement, you will get one coin. If you make a false statement, you will get nothing.

What sentence can guarantee you getting the gold coin?