Question

Aflati x daca media ponderata a numerelor 3, 4 si x cu ponderile 2, x si 3 este 2.

Answer 1

2= (3*2+4*x+x*3) : (2+x+3)
2=(6+4x+3x): (x+5)
2(x+5)=6+7x
2x+10=6+7x
10-6=7x-2x
4=5x
x=4/5