Help with electricity question ?

Hi I'm stuck on question 15 on this link.

https://251cff15a8166ff37f9e29258122a776151522fa.googledrive.com/host/0B1ZiqBksUHNYdlM2Sk5PZkxyTFk/Set-C/Electricity.pdf

There are answers on the website too but I still don't get it and my physics exam is on Tuesday please help

I've got the first part 150V however I cannot figure out how to get 25V for the voltage across each filament.

Thank you for any help provided I appreciate it.

Hello there,

It seems to me, as if you simply need to apply $V = IR$ to each component. For the resistor, $V_R = (0.50)(300) = 150 V$ and for the filaments, $V_F = (0.50)(50) = 25 V$. May I ask about your method for the first answer? The method that I have described applies to both components and I am wondering why you were able to get one answer but not the other.

I used V=IR for my first answer, I clearly was over thinking the question thank you for the help