Răspuns :
[tex]\frac{1}{80} +\frac{1}{61}+\frac{1}{78} =\frac{2379+3120+2440}{190320} =\frac{7939}{190320} aproximativ 0,041714[/tex]
[tex]\frac{1}{80} +\frac{1}{61}+\frac{1}{78} =\frac{2379+3120+2440}{190320} =\frac{7939}{190320} aproximativ 0,041714[/tex]