Question

Trei numere au suma 74.Media aritmetica a primelor doua este 21, iar media aritmetica a ultimelor doua este 28.Aflati cele treu numere

Answer 1

Fie a ,b,c numerele

a+b+c=74
(a+b)/2=21
a+b=42 =>a=42-b
(b+c)/2=28
b+c=56 =>c=56-b

42-b+b+56-b=74
98-b=74
b=24
a=18
c=32

Answer 2

Notez cu a, b, c-nr.
a+b+c=74
(a+b)/2=21=>a+b=21*2=42
(b+c)/2=28=>b+c=28*2=56
a+b+c=74
a+b=42
c=74-42=32
a+b+c=74
b+c=56
a=74-56
a=18
b=74-(18+32)=74-50=24