Voltage direction and power sign in circuit analysis

[Air]

I have the following circuit:

My question is, what do I take the voltage direction to be? For the center component, it is 200V in a positive direction being upwards so does that mean that for the other components (20A and 10A), it is also in that direction?

Thanks in advance.


EDIT: I have one more question - When voltage is in the direction of current, is the power equal to +Vi or -Vi?

 

[Delphi51]

I don't understand the components - are they batteries, meters or what? Hmm, can't be meters because you can't run 80 A through a Voltmeter or put 200 Volts across an Ammeter!

It appears that the + and - markings indicate the voltage polarity and the arrows indicate the direction of standard (positive) current.