bonsoir
Loire Vistule et Tage = x
Douro, Meuse, Ebre = x - 100
Elbe = x + 100
Rhin = x + 200
Danube = 3 x
3 x + 3 ( x - 100 ) + x + 100 + x + 200 + 3 x = 11 000
3 x + 3 x - 300 + x + 100 + x + 200 + 3 x = 11 000
11 x = 11 000 + 300 - 100 - 200
11 x = 11 100
x = 1 000
Loire Vistule et Tage = 1 000 km
Douro, Meuse et Ebre = 900 km
Elbe = 1 100
Rhin = 1 200
Danube = 3000
