Why is the Hole below a Lock?

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?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

What does this mathematical rebus means ?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

There is a river to cross using a river raft and there are eight people (father, mother, policeman, thief, 2 daughters and 2 sons). No one knows to operate the raft except the adults and also excluding the thief. Only two people can go in the raft at a time. The raft should keep coming back and forth in order to pick and drop the people.
Rules to be followed:
Father: the father cannot stay in the raft or outside the raft without the presence of the mother.
Mother: the mother cannot stay in the raft or outside the rat without the presence of the father.
Thief: the thief is not allowed to stay with any of the family members unless there is a policeman.
Policeman: the policeman can travel with anyone.
2 sons and 2 daughters: they are not allowed to travel in the raft without the presence of an adult. They cannot either travel in the presence of only thieves without the policeman. The sons cannot be with their mothers without their father's supervision. The daughters are not allowed to be there with their fathers without the supervision of their mothers. But the daughters and the sons can be left unsupervised (as long as the other rules are applied).
What is the sequence that the people should follow in order to cross the river through the raft keeping in mind all the rules?
The rules are applicable not only in the raft but also outside the raft.

A system error causes the change of John's net banking password. To sort this out, he calls the customer care. The following is the conversation he had with the executive:

John: My password has been changed.

Custom Care Executive: We have kept your password distinct this time. It has 8 letters out of which, 3 letters are the same as the previous one.

John: Okay, thanks.

Can you determine the old as well as the new password of John's net banking account after reading the conversation carefully?

If two's company, and three's a crowd, then whats four and five ?

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

A Child was born in Lahore, Pakistan. Still, the child is not a Pakistani citizen. why?