If it took eight men ten hours to build a wall, how long would it take four men to build it?

Can you replace the question mark with the correct number in the below table sequence?

Suppose we lay down two cups in front of you. One of the cups is filled with tea and the other one with coffee. Now we ask you to take a spoonful of tea and mix it with the coffee. At this moment, the coffee cup has a mixture of tea and coffee. You have to take that mixture (spoonful) and add it back to the tea.

Can you now tell if the cup of coffee has more tea or the cup of tea has more coffee?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

What English word has three consecutive double letters?

A chess tournament is taking place on knock-out terms (the one who loses the match is out of the game).
(a) If 10 matches are played in total, how many players participated?
(b) If 20 players took part in the tournament, how many matches were played?

Find the hidden panda in the image below.

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Using mathematical symbols like +, -, and x in order to make the equations correct. Replace # with the above-given symbols.

9 # 8 # 7 # 6 # 5 # 4 = 91

I travel all around the world but always stay in the corner. What am I?