What is the difference between ...

tactic and strategy?

Thanks for your answers... 

Tactic lasts for ~max. 10 moves, strategy can last for 40.

That's tactics:

Tactics is a short term series of moves, often sacrifices to gain an immediate win or very good game.

Strategy is long term planning.  

Quite often when you are following long term strategy, tactics will come up.

Note: tactics favorable to you should only come up when the other side has made a mistake. 

Tactics can last more than 10 moves but usually under 10 moves. Usually more like 2-4 moves. Sometimes 1 move.

The correct answer is:

All tactics are strategies

But not all strategies are tactics

Very similar to:

All ants are insects

But not all insects are ants

Think of strategies as the limbs and branches of the tree. Tactics are the leaves

Many times tactics are the culmination of successful strategies.

Excellent answers friends... thank you very much!