First find how far Glenda goes in 3 hours by multiplying her speed by the number of hours she travels: 3 hours * 8 miles/hour = <<3*8=24>>24 miles
Then do the same thing for Ann: 3 hours * 6 miles/hour = <<3*6=18>>18 miles
Now add the number of miles both people skated to find the total distance between them: 18 miles + 24 miles = <<18+24=42>>42 miles
#### 42