notam cu x=nr. teme I=3x/9 II=1/2(x-3x/9) II=6x/18 III=1/2(x-6x/18) IIi=12x/36 IV=10 x-3x/9+6x/18+12x/36=10 aducem la acelasi numitor 36x-12x+12x+12x=360 48x=360 x=360/48 x=7,5 I=3/9*7,5 I=2,5 II=6/18*7,5 II=2,5 III=12/36*7,5 III=2,5 IV=10 I+II+III+IV= 2,5+2,5+2,5+10=17,5 e ceva gresit la a doua saptamana jumatate inseamna 1/2 iar 0,(6)=6/9 jumatate ar fi fost 0,5