Question

Media aritmetica a numerelor a b c este 95.Aflati numerele stiind ca intre multimile {a; b+2; c+13} si {15; 12; 18} ae stabilieste o proportionalitatea directa.

Answer 1

a/15 = (b+2)/12 = (c+13)/18
12a=15b+30              a=(15b+30)/12
18b+36=12c+156      c=(18b-120)/12
18a=15c+195            
(a+b+c)/3=95
a+b+c=285
(15b+30)/12+b+(18b-120)/12=285
15b+30+12b+18b-120=3420
45b=3510
b=78
a=(15b+30)/12 =(15*78+30)/12=100
c=(18b-120)/12=(18*78-120)/12=107

a=100
b=78
c=107