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

One day, Birbal got late for a function and Akbar was highly disappointed.
Please forgive me Jahanpanah. I arrived late because my child was crying and I had to calm him down, explained Birbal.
Does it take this long to placate a child? questioned the emperor. I feel that you have no idea about how to raise a child. I order you to act like a child and I will act like your father to show you how you should have dealt with your child. Come on! Ask me all that he asked from you.
Father, I want a cow, said Birbal.
The emperor quickly ordered one of the servants to bring a cow to the kingdom.
I want to drink its milk, now, now, now! said Birbal, imitating the voice of his child.
Akbar asked his servants to milk the cow and give to Birbal.
The servants quickly milked the cow and offered the milk to Birbal. He sipped in a little and then gave the bowl to the emperor.
As Birbal put up the next demand that was put up by his child a few hours ago, the emperor was stunned and left the room.
What did Birbal say?

What is always in front of you but can’t be seen?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

Complete the given grid with valid words. You can only use the letters AAEEIIMMPPTT.

Hint: The grid reads the same across as down.

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

Can you identify the hidden rebus in the image below?