Matt ran the first 3 1/2 miles of a 5 -mile race in 1/3 hour. What was his average rate, in miles per hour, for this first part of the race?

The Average Rate Matt ran   =  10 1/2 miles per hour

Step-by-step explanation:

Matt's average rate, in miles per hour is referred to as Average  Speed which is given as

Average  Speed =Distance /Time

Distance for the first part of journey  =  3 1/2 miles

Time  = 1/3 hour

Average Rate ( Speed)  =   3 1/2 miles  ÷ 1/3

 = 7/2   ÷ 1/3

= 7/2 x 3/1

= 21/2  =  10 1/2 miles per hour .