Your mistake is in the first step, calculating current. Are there different currents at different points in the circuit?
For #10, I’m going to repeat my questions above. Can you answer any of these 3 questions?
Question 10 gives you the relative resistances of the two loads in a 240 circuit, and asks for the voltage drop across each one. Here’s a way to think through it.
1. What will be the combined drop across both loads? (Kirchoffs Law)
2. What would each load drop if they were equal resistance?
3. These are not equal – the resistance of one is two times the other. How would the voltage drop divide up between them?