Question 404954
Since Sue is traveling at 3mph, she is going at 3 miles=60 minutes. 
This means that Sue is going at 1 mile in 20 minutes. 
Now all you have to do is figure out how many 20-minute miles fit into 2.5 miles. 
1+1+.5=2.5
Your one equals 20 minutes, so just solve from there. 
20 minutes + 20 minutes + 10 minutes = 50 minutes
That's your answer.