Notăm cele trei numere cu a, b, c.
[tex]\it \dfrac{a+b}{2} =32 \Rightarrow a+b = 64 \ \ \ \ \ (1)
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\dfrac{b+c}{2} =39 \Rightarrow b+c = 78 \ \ \ \ \ (2)
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\dfrac{c+a}{2} =41 \Rightarrow c+a = 82 \ \ \ \ \ ( 3)[/tex]
[tex]\it (1), \ (2),\ (3) \Rightarrow 2a+2b+2c = 64+78+82|_{:2}\Rightarrow a+b+c=
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= 32+39+41 \Rightarrow a+b+c = 112 \ \ \ \ \ (4)
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(1),\ (4) \Rightarrow 64+c = 112 \Rightarrow c = 112-64 \Rightarrow c = 48[/tex]
[tex]\it (2),\ (4) \Rightarrow a+78 = 112 \Rightarrow a = 112-78 \Rightarrow a = 34
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(3),\ (4) \Rightarrow b+82 = 112 \Rightarrow b = 112-82 \Rightarrow b = 30[/tex]
Deci, numerele cerute sunt:
a= 34, b = 30, c = 48.
