Complete the table series riddle by finding the number that can replace "??".

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

I look at you, you look at me I raise my right, you raise your left. What am I?

You can hear me, but you can't touch or see me.

What am I?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

Name the three-letter word that can complete the below words:

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

Can you count the number of quadrilaterals in the picture below?

Can you solve the photo plexer logic ?

People are waiting in line to board a 100-seat aeroplane. Steve is the first person in the line. He gets on the plane but suddenly can't remember what his seat number is, so he picks a seat at random. After that, each person who gets on the plane sits in their assigned seat if it's available, otherwise, they will choose an open seat at random to sit in. The flight is full and you are last in line. What is the probability that you get to sit in your assigned seat?

Which tank will fill first?