[tex]\displaystyle \\
P=U \times I \\ \\
I= \frac{P}{U} = \frac{40}{220} = \frac{4}{22}=\boxed{\frac{2}{11}\,A}= \boxed{0,18\,A} ~~~\boxed{b)} \\ \\
R= \frac{U}{I} = \frac{220}{ \frac{2}{11} } = \frac{220 \times 11}{2}=110 \times 11 = \boxed{1210\; \Omega } = \boxed{1,21 \,K\Omega }~~~\boxed{a)} \\ \\
\texttt{Rezistenta echivalenta a celor 5 becuri este: } \\ \\
R_e = \frac{R}{5} = \frac{1210}{5} = \boxed{242 \,\Omega} ~~~ \boxed{c)} [/tex]
