Step-by-step explanation:
[tex] = \frac{20}{5} . {2}^{ - 3} [/tex]
[tex] = 4. \frac{1}{ {2}^{3} } [/tex]
[tex] = \frac{4}{2 \times 2 \times 2} [/tex]
[tex] = \frac{4}{8} [/tex]
[tex] = \frac{1}{2} [/tex]
