Explicație pas cu pas:
a)
[tex]A = \frac{1}{2} \cdot \frac{\not3}{4} \cdot \frac{ \not 5}{\not6} \cdot \frac{7}{8} \cdot \frac{9}{\not10} = \\ = \frac{1}{2} \cdot \frac{1}{4} \cdot \frac{1}{2} \cdot \frac{7}{8} \cdot \frac{9}{2} = \frac{7 \cdot 9}{ {2}^{8} } = \frac{63}{256} [/tex]
[tex]B = \frac{2}{ \not 3} \cdot \frac{4}{\not 5} \cdot \frac{\not 6}{7} \cdot \frac{8}{9} \cdot \frac{\not 10}{11} = \\ = \frac{2}{1} \cdot \frac{4}{1} \cdot \frac{2}{7} \cdot \frac{8}{9} \cdot \frac{2}{11} = \frac{ {2}^{8} }{7 \cdot 9 \cdot 11} = \frac{256}{693} [/tex]
b)
[tex]A \cdot B = \frac{7 \cdot 9}{ {2}^{8} } \cdot \frac{ {2}^{8} }{7 \cdot 9 \cdot 11} = \bf \frac{1}{11} \\ [/tex]
