Răspuns:
Explicație pas cu pas:
0,5 = 5/10 = 1/2
0,(3) = 3/9 = 1/3
2a = 3b = c/2 = d/3 = k
a = k/2
b = k/3
c = 2k
d = 3k
a + b + c + d = 7
k/2 + k/3 + 2k + 3k = 7
3k/6 + 2k/6 + 12k/6 + 18k/6 = 7
35k/6 = 7
k = 7 : 35/6 = 7*6/35 = 6/5
a = (6/5)/2 = 6/5 : 2 = 6/5*1/2 = 6/10 = 0,6
b = (6/5)/3 = 6/5 : 3 = 6/5*1/3 = 6/15 = 0,4
c = 2*6/5 = 12/5 = 2,4
d = 3*6/5 = 18/5 = 3,6