I'm sorry if I was being oversimplistic - I worked on the basis that a nautical mile is 1 minute of arc therefore 1 degree, having sixty minutes, equals 60 nautical miles :o)
I think the answer they want is 60nm. But sddsddean is going around the equator rather than pole to pole. Dustybun is right, the n.mile was defined as 1 min. or arc (latitude-wise) and is taken as the average value (1852m) - distance at the bulging equator will actually be slightly greater.
Sorry, I missed the 'nautical' in your question. 69.166666statute miles = 60.0657nm. If you are not going to worry about the odd 400 feet difference between this and 60nm, I'm certainly not!