Question

Media aritmetica a cinci numere este 162.Aflati numerele,stiinsd ca primele 3 sunt direct proportionale cu numerele 3,4,5 ,iar ultimele sunt direct proportionale cu 3,4,5.

Answer 1

(a+b+c+d+e)=5*162
a/3=b/4=c/5=k⇒a=3k   b=4k   c=5k
c/3=d/4=e/5=k₁⇒c=3k₁   d=4k₁      e=5k₁
5k=3k₁⇒k₁=5/3k
c=5/3*3k=5k
d=4*5/3k=20/3k
e=25/3k
3k+4k+5k+20/3k+25/3k=810 |x3
12x3k+45k=2430
81k=2430⇒k=30
a=90   b=120        c=150    d=200     e=250
(90+120+15+200+250)/5=162