Question

4 elevi au in preuna 138 de timbre.Daca primula ar primi de la ceilanti 3 cate 2 timbre a tunci nr timbrelor ar fi 4nr naturale consecutive. Acum aflati cate timbre are fiecare elev.

Answer 1

a+b+c+d= 138

a+3*2 + b-2+c-2+d-2 = a+a+1+a+2+a+3

a+6 + b-2+c-2+d-2 =4a+6
a+b+c+d=4a+6
138=4a+6
4a=138-6
4a=132 |:4

a=33
b=34
c=35
d=36
______
T : 138

Answer 2

a+b+c+d=138
a+6=primul
a+5=al doilea
a+4=al treilea
a+3=al patrulea 
inlocuim in relatia   a+b+c+d=138 si avem
a+6+a+5+a+4+a+3=138
4a=138-6-5-4-3
4a=138- 18
4a=120
a=120/4
a=30

30+6=36 primul
30+5=35 al doilea
30+4=34 al treilea
30+3=33 al patrulea 

proba  36+35+34+33=138