Answer :

205 miles = x
    1 h         3h
Cross multiply and divide, would give the answer to x
205 × 3 = 615

Therefore, the race car can travel 615 miles in 3 hours if the speed stay constant.
NOTE - I am assuming that 205 MPH is a constant speed.
Simply multiply MPH and hours traveling:
205 x 3 = 615
The car will travel 615 miles in 3 hours if it is traveling at a constant rate of 205 MPH.
Hope this helps!
~ArchimedesEleven