I nr = a
II nr = a + 1
III nr = a + 2
IV nr = a + 3
V nr = a + 4
[tex] \frac{a + (a + 1) +( a + 2) + (a + 3) + (a + 4)}{5} =19[/tex]
[tex] \frac{5a + 10}{5} =19[/tex]
[tex]5a + 10 = 19*5[/tex]
[tex]5a + 10 = 95[/tex]
[tex]5a = 95 - 10[/tex]
[tex]5a = 85 =\ \textgreater \ a = \frac{85}{5} =17[/tex]
I nr = 17
II nr = 17 + 1 = 18
III nr = 17 + 2 = 19
IV nr = 17 + 3 = 20
V nr = 17 + 4 = 21
