Primul robinet = 20l /min => 20•30 l in 30 min= 600 l in 30 min
Al doilea= 4/5 • 20= 16l/min => 16l • 30 in 30 min= 480 l in 30 min
Al treilea= 3/4 • 16l/min= 12 l/min => 12l • 30 in 30 min = 360 l
Capacitate= 2kl= 2000l
L apa necesari= capacitate - (primul robinet+al doilea+ al treilea) =
2000l - (600+480+360)= 2000 l - 1440 l = 560 l