When running a half marathon (13.1 miles), it took Frank 8 minutes to run from mile marker 1 to mike marker 2, and 19 minutes to run from mile marker

2 to mile marker 4. a. How long did it take Frank to run from mile marker 1 to mile marker 4? b. What was Frank's average speed as he ran from mile marker 1 to mile marker 4? c. 68 minutes after starting the race, Frank passed mike marker 9. To compete the race in 113 minutes, what must Frank's average speed be as he travels from mile marker 9 to the finish line?