Найдите среднее орифмитическое 1.3/7и2.5/21

Question

Найдите среднее орифмитическое 1.3/7и2.5/21

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Answer 1

M=1.3/7+2.5/21:2=1.9/21+2.5/21:2=3.14/21:2=3.2/3:2=11/3:2=11x1/3x2=11/6=1.5/6