Question

Aflati trei numere naturale stiind ca doua cate doua au media aritmetica A) 13; 14si 16 B) 15; 19 si 25 .

Answer 1

a)Fie numerele a,b si c
(a+b)/2=13 =>a+b=26 =>a=26-b
(b+c)/2=14 =>b+c=28
(a+c)/2=16 =>a+c=32 =>a=32-c
=>26-b=32-c =>c-b=6 =>c=b+6
Dar stim ca b+c=28 =>b+b+6=28 =>2b=22 =>b=11 =>c=17 =>a=15

b)Fie numerele a,b si c
(a+b)/2=15 =>a+b=30 =>a=30-b
(b+c)/2=19 =>b+c=38
(a+c)/2=25 =>a+c=50 =>a=50-c
=>30-b=50-c =>c-b=20 =>c=20+b
Dar stim ca b+c=38 =>b+20+b=38 =>2b=18 =>b=9 =>c=29 =>a=21