How would you explain the answer to this question?

If a motorist had driven 1 hour longer on a certain day and at an average rate of 5 miles per hour faster, he would have covered 70 more miles than he actually did. How many more miles would he have covered than he actually did if he had driven 2 hours longer and at an average of 10 miles per hour faster on tht day?

A. 100
B. 120
C. 140
D. 150
E. 160

Answer D