Question 43997
OK, so the current varies inversely with the resistance. We can write: 
{{{I=x/R}}}
where x is a fixed constant value.
Rearranging:
{{{x=IR}}}
When I=230, R=1/2, and this tells us that x=230/2=115
so when R=540, 
{{{I=115*540}}}
Giving the solution I=62100 amps

I hope this helps.

I would be extremely grateful if you would send me your feedback on my help to adam.chapman@student.manchester.ac.uk.