Răspuns:
Bună,
[tex]( \frac{1}{5} + \frac{1}{55} + \frac{1}{555}) \times \: \frac{5}{2} = \\ \frac{1}{5} \times \frac{5}{2} + \frac{1}{55} \times \frac{5}{2} + \frac{1}{555} \times \frac{5}{2} = \\ \frac{1}{2} + \frac{1}{22} + \frac{1}{222} = \\ \frac{1221 + 111 + 11}{2442} = \frac{1343}{2442} [/tex]
Sper că te-am ajutat. <3
