How much current does the speaker draw? How much power does the speaker use

A 20 ohm speaker is connected in series with a 40 ohm resistor and a 9V DC source.

How much current does the speaker draw?

How much power does the speaker use?

Please show me the math behind it, thanks!

This is a simple circuit, all you have to do is use the basic ohms law.

you take the two resistors and you add them together so it will become 60 ohm.

v=Ir

using this we can find the current
v/r = I

I= 9/60 = 0.15 A

Now to find the power, we can use this formula:

P = (I^2)*R

Where are is the resistance of the speaker.

So

P= (0.15^2)*20 = 0.45W

Hope I helped.