Răspuns :

4b.............3h...........3kw
6b..............20h.........x

In primul rand aflam cat consuma 6 becuri in 3 ore.

4b..........3h........3kw
6b..........3h........x

Deoarece la mijloc avem 3h si 3h in ambele randuri nu il consideram, deci;

x=[tex] \frac{6X3}{4}[/tex]⇒[tex]x= \frac{18}{4} [/tex]

Acum ca stim cat consuma 6 becuri in 3 ore putem afla cat consuma in 2o ore:

6b.........3h..........[tex] \frac{18}{4} [/tex]kw
6b.........20h.........x

x=[tex] \frac{20 \frac{18}{4} }{3} [/tex]⇒x=30kw