+118723 I don't know about all these terms but I can put the numbers where the question tells me to and this is what I get
$${\frac{{\mathtt{10}}}{{\sqrt{{\mathtt{1}}{\mathtt{\,-\,}}{\frac{{\mathtt{4.2}}}{{\mathtt{9.5}}}}}}}} = {\mathtt{13.388\: \!251\: \!678\: \!948\: \!521\: \!8}}$$
So I think that 13.39 seconds will have passed on Earth.
I am sure Alan will tell me if I have misinterpreted. (and that will be a good thing) 
+118723 I don't know about all these terms but I can put the numbers where the question tells me to and this is what I get
$${\frac{{\mathtt{10}}}{{\sqrt{{\mathtt{1}}{\mathtt{\,-\,}}{\frac{{\mathtt{4.2}}}{{\mathtt{9.5}}}}}}}} = {\mathtt{13.388\: \!251\: \!678\: \!948\: \!521\: \!8}}$$
So I think that 13.39 seconds will have passed on Earth.
I am sure Alan will tell me if I have misinterpreted. (and that will be a good thing)
