Quarantine Mathematics

How fast and intelligent should a goalie be in the game without a goalie?


The mid-back of the blue team shoots at a distance of 7m from the goal at a speed of 120km/h, and the left-back at that moment starts running at a speed of 25km/h to replace the goalkeeper and exits the court 1m from the centre line.

On the other hand, the ball goes past the goal and it takes him 1.5 sec to get back into the court and to be under the goalkeeper’s control 1 m from the left goal post.

At that moment he has to decide whether to try to score a goal.

The speed at which he can throw the ball is 80km/h, but as the opposing goal is far, he shoots to the middle of the goal.

The blue goalie has run into the court 2m from the centre line and runs at 25km/h and the last place he can defend the shot of the opposing goalkeeper is 2m away from the goal.

What is the time the red goalie has for deciding whether to shoot or not?