1.3 robinete.......7 ore
21 robinete......x ore
Marimile sunt invers proportionale deci
21/3=7/x
x=1 ore
2. 120 rotatii......6 minute
100 rotatii.......x
x=100*6:120=600:120=5 minute
3. 5/x=55/121
x=5*121:55=11
(2x+3)/9=33/27
27(2x+3)=9*33
54x+81=297
54x=216
x=3.92
4.Elena=1,65m
Mihai=60/100*1.65=0.99m
Elena/Mihai=1.65/0.99
Suma inaltimilor=1,65+0.99=2.64m
Elena/Suma=1.65/2.64
