Two​ joggers, one averaging 8 mph and one averaging 4 ​mph, start from a designated initial point. The slower jogger arrives at the end of the run 35 minutes after the other jogger. Find the distance of the run.

22.5 miles long

basically all you have to do is count out the factors until you reach two number of 45 apart

DIFFERENCE
7MPH 5MPH BETWEEN THEM

7 5 2
14 10 4
21 15 6
28 20 8
35 25 10
42 30 12
49 35 14
56 40 16
63 45 18
70 50 20
77 55 22
84 60 24
91 65 26
98 70 28
105 75 30
112 80 32
119 85 34
126 90 36
133 95 38
140 100 40
147 105 42
154 110 44
161 115 46

considering the differences are even it means it has to fall in the middle. if you count from the top it is 22.5 numbers down giving you the number of miles.
I'm sure there is an easier way but this is how i would solve it. :)