Why football is played for 45 minutes?

Those who thought of this must have lots of time
Why people play football for 45 minutes, not 30 minutes or 1 hour?
Even the sports scientist and some of the senior players could not give
the right answer.

In that confusing situation one person came up with a reasonable answer.
He said......."The reason people play this game for 45 minutes is... There
are 2 teams and there are 11 players in each team. Each player brings his
own "2 balls" So in total there are 44 balls.

"There is one ball on the ground itself. Thus the grand total is 45".

Question Answered !!!
sometimes there is extra time of 2mins which is the referee's balls!