1. 3 kg banane .... 8,1 lei
5 kg banane.... x lei
3/5=8,1/x
=> 3x=5•8,1
X=5•8,1/3=13,5 lei
2. 6 muncitori.... 10 zile
15 muncitori..... x zile
6/15=15/x
15x=6•10
X=60/15=4 zile
3. 3 bazine..... 24 kg vopsea
6 bazine..... x kg vopsea
3/6=24/x
3x=6•24
X=6•24/3=48 kg vopsea
4. 5 robinete... 6 ore
10 robinete.... x ore
5/10= x/6
10x=5•6
X=30/10
X=3 ore