Question

Zapisz wszystkie liczby w postaci dziesiętnej i oblicz ich średnią
arytmetyczną.

Answer 1

Średnia arytmetyczna - to suma liczb podzielona przez ich liczbę.

a)

[tex]\frac{3}{4} = \frac{3\cdot25}{4\cdot25} = \frac{75}{100} = 0,75\\\\\frac{7}{2} = \frac{7\cdot5}{20\cdot5} = \frac{35}{100}=0,35\\\\sr = \frac{0,75+0,28+0,35}{3} = \frac{1,38}{3} = \boxed{0,46}[/tex]

b)

[tex]\frac{23}{25} = \frac{23\cdot4}{25\cdot4} = \frac{92}{100} = 0,92\\\\\frac{4}{5} = \frac{4\cdot2}{5\cdot2} = \frac{8}{10} = 0,8\\\\\frac{11}{50} =\frac{11\cdot2}{50\cdot2} = \frac{22}{100} = 0,22\\\\sr=\frac{0,92+0,8+0,82+0,22}{4} = \frac{2,76}{4} = \boxed{0,69}[/tex]

c)

[tex]\frac{1}{8} = \frac{1\cdot125}{8\cdot125} =\frac{125}{1000} = 0,125\\\\\frac{9}{10} = 0,9\\\\\frac{3}{5} = \frac{3\cdot2}{5\cdot2} = \frac{6}{10} = 0,6\\\\sr =\frac{0,36+0,125+0,9+0,6+0,7}{5} = \frac{2,685}{5} = \boxed{0,537}[/tex]

d)

[tex]\frac{1}{20} = \frac{1\cdot5}{20\cdot5} = \frac{5}{100}=0,05\\\\1\frac{1}{4} = 1\frac{1\cdot25}{4\cdot25} = 1\frac{25}{100} = 1,25\\\\2\frac{1}{50} = 2\frac{1\cdot2}{50\cdot2} = 2\frac{2}{100} = 2,02\\\\3\frac{1}{8} = 3\frac{1\cdot125}{8\cdot125} = 3\frac{125}{1000} = 3,125\\\\4\frac{1}{25} =4\frac{1\cdot4}{25\cdot4} = 4\frac{4}{100} = 4,04[/tex]

[tex]sr =\frac{0,05+1,25+2,02+3,125+4,04}{5} = \frac{10,485}{5} = \boxed{2,097}[/tex]