Question 1136612

Sarah left Minneapolis heading east on the interstate at a speed of 60 mph. Her sister followed her on the same route, leaving three hours later and driving at a rate of 75 mph. How long, in hours, will it take for Sarah's sister to catch up to Sarah? 
<pre>2 hours, as suggested by someone is WRONG!!! For the sister to take 2 hours, she'd have to be traveling @ 150 mph. 
Isn't that dangerous and illegal? They're not on a racetrack, I'm sure, just the interstate! Not even on the AUTOBAHN can they go that fast!
Even that's VERY HIGH speed on the AUTOBAHN (average speed: 150 km/h or 80 mph)
I hope you realized this and have IGNORED that answer!
Correct answer: 12 hours!