Răspuns :
4 robinete...........24 ore
? robinete...........8 ore
24:8=3 4·3=12
R:12 ore
? robinete...........8 ore
24:8=3 4·3=12
R:12 ore
4R........................24h
XR.........................8h
___________________
8X=24x4
8X=96
X=96:8
X=12 robinete
XR.........................8h
___________________
8X=24x4
8X=96
X=96:8
X=12 robinete