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a/2=b/5 si b/10=c/7
a) a+b+c=210, aflati numerele
b) media aritmetica a nr. a; b; c daca a²+b²+c²=16500


Răspuns :

a)a=2b/5
c=7b/10

2b/5 + b+ 7b/10=210  aducem la acelasi numitor
4b+10b+7b=2 100
21b=2 100
b=100
a=2*100/5= 2*20=40
c=7*100/10= 7*10=70

b)ma= (a+b+c)/3=  (100+40+70)/3= 210/3= 70