I have decided to learn electronics from scratch again and have started with resistors. I was practising simplifying different circuits of parallel and series resistors when I came across this one. After simplifying so far I got stuck. Is this where you use Kirchhoff's loop rule or is there an easier way or am I missing something? (the reason I am unsure whether to use the loop rule is because all the examples I have seen have two different batteries in the circuit). Thanks for any help.