I may be wrong, since I'm not used calculating in miles and inches. As far as I know 1 mile should have 63360 inches (google said so...)
Since the diameter is 25, then the radius is 12.5. Then circumference of the tire is:
Now 207 miles are : 1.311552 *10^7 inches.
If you divide the whole distance with the circumference, you get the number of turns your car did. (1.67* 10^5)
Multiplicate this by 360 and you get your wished degrees. (6.01 *10^7)
For the second question, ask your teacher whether you are supposed to have constant speed during that hour or not. Since it necessary to know. If the speed is not constant, you can't find out. So we suppose it is constant:
55000 times make a distance of :
Divided by 63360 you get 68.2 miles in one hour. That's your speed 68.2 mph