Defective Coin

There are nine gold coins of same weight, in that one of the coin is defective (means either it is more weight or less weight than others).

you have to find the defective gold coin among nine coins, A physical balance is given to you, and you have to use the balance only three time. How will you find the defective coin?

LEAK TANK

A tap can  fill a Tank completely in 2 hours, But because of the Leak in the Tank, the tap took 2 hrs and 30 mins.
If the Tank was full, How long  would it take to drain the tank through the LEAK?