Răspuns:
(a+b)/(b-c) = 8
Explicație pas cu pas:
a/3 = b/5= c/4
0,25 = 25/100 = 1/4
0,(3) = 3/9 = 1/3
a/3 = b/5 => a = 3b/5
b/5 = c/4 => c = 4b/5
(a+b) /(b-c) = (3b/5 + ⁵⁾b) / (⁵⁾b - 4b/5) =
= (3b+5b)/5 / (5b-4b)/5 =
= [(3b+5b)/5]·[5/(5b-4b)] =
= 8b/b = 8
