What four weights can be used to balance from 1 to 30 pounds?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

What has many keys but can’t open a single lock?

John leaves home and then he takes three right turns. John wants to return to home but he was scared of Jacob, who is wearing a mask.

What is John Situation ?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

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

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

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

What am I?

What does this rebus means ?