Risolvere un div by 0

[Urzetto]

ragazzi nella 3 riga c'è un div by zero, come correggo?

function GetMissionDuration ($GameSpeed, $MaxFleetSpeed, $Distance, $SpeedFactor) {
    $Duration = 0;
    $Duration = round(((35000 / $GameSpeed * sqrt($Distance * 10 / $MaxFleetSpeed) + 10) / $SpeedFactor));

    return $Duration;
} 

grazie milla