Răspuns :
I+II+III+IV=986 ELEVI
I+II+III=751 ELEVI
II+III=498 ELEVI
III+IV=525 ELEVI
IV=986-751
IV=235 ELEVI
III=525-235
III=290 ELEVI
II=498-290
II=208 ELEVI
I =986-(208+290+235)=986-733
I=253
PROBA
253+208+290+235+=986 ELEVI
I+II+III=751 ELEVI
II+III=498 ELEVI
III+IV=525 ELEVI
IV=986-751
IV=235 ELEVI
III=525-235
III=290 ELEVI
II=498-290
II=208 ELEVI
I =986-(208+290+235)=986-733
I=253
PROBA
253+208+290+235+=986 ELEVI
a+b+c+d=986
A+b+c=751
b+c=498
C+d=525
751+d=986; d=986-751=235cl a patra-d-235;c+235=525;c=525
--235;c=290;
B+290=498;b=498-290;b=200;a+290+200=751;a+490=751;a=751-490;a=161.
161+200+290+235=986(proba)