Răspuns:
[tex] \frac{2}{3} \times 5 + \frac{2}{5} \times 7 + \frac{2}{7} \times 9 + \frac{2}{85} \times 87 = \frac{10}{3} + \frac{14}{5} + \frac{18}{7} + \frac{174}{85} = \frac{19192}{1785} [/tex]
