Question

Trei numere au doua cate doua media aritmetica egala cu 18,30 respectiv 24.Aflati numerele.

Answer 1

ma(a,b)=(a+b)/2=18 => a+b=36 (I)
ma(b,c)=(b+c)/2=30 => b+c=60 (II)
ma(a,c)=(a+c)/2=24 => a+c=48 (III)
din II => b=60-c (IV)
din III => a=48-c (V)
inlocuim relatiile IV si V in I:
48-c+60-c=36 => 48+60-36=2c => 2c=72 => c=36
b=60-36=24
a=48-36=12