Answer :
Assume the radius of the the earth is ~4000 miles.
radius of orbit = 4000 +200 = 4200 miles
In 4 hrs it orbits 2Pi*r =2pi*4200= 8400pi miles
In 1 hr it would travel (8400pi/4 )
= 2100pi = 6597.3445 miles (exact value)
= 6597 miles ( approximate)