How can you take 2 from 5 and leave 4?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Suppose you are sitting in an interview and the interviewee asks you an aptitude question.

You have three buckets with a capacity of 4 litres, 8 litres and 10 litres and you have a large tank of water. Now you have to measure 3 litres of water precisely using those buckets. How will you do it?

You need to remove two matchsticks to make the below equation true. Can you do it ?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

What does below rebus means ?

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

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

Can anyone tell me a word in the English dictionary which has a silent 'z'?

I have branches, but no fruit, trunk or leaves. What am I?