v_{k e s k} = \frac{4}{\frac{1}{v_{1}} + \frac{1}{v_{2}} + \frac{1}{v_{3}} + \frac{1}{v_{4}}} = \frac{1680}{319} = 5, 3 \frac{m}{s}

${v_{kesk} = \frac{4}{\frac{1}{v_1} + \frac{1}{v_2} +\frac{1}{v_3} +\frac{1}{v_4}} = \frac{1680}{319} = 5,3\,\mathrm{\frac{m}{s}}}$

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