His distance from one end is ' D ', and his distance from the other end is ' 2D '.
The distance from one end to the other end is (D + 2D) = 3D .
3D = 1,049 miles
Divide each side by 3 :
D = 1,049 / 3 = 349 and 2/3 miles .
The question doesn't tell which end he started from, and where he's headed,
so I guess you have to know that this is the Iditerod race, it STARTS in Anchorage,
and it ENDS in Nome.
He is ' 2D ' from Anchorage, so he has completed [ 2 x (349 and 2/3 miles) ] =
699 and 1/3 miles.
Rounded to the nearest mile, that's 699 miles.