###Human: Rudy runs 5 miles at a rate of 10 minutes per mile. Later he runs 4 miles at a rate of 9.5 minutes per mile. What is the total length of time that Rudy runs?, ### Assistant: Rudy first runs for 5 * 10 = 50 minutes.
Then Rudy runs for 4 * 9.5 = 38 minutes.
Rudy runs for a total length of 50 + 38 = 88 minutes 
 So the answer is :  88