Diana usually drives at an average rate of 30 mph. Yesterday she drove for 2 hours and 40 minutes. What distance did she travel?
First, we need to convert the 40 minutes into hours. There are 60 minutes in an hour, so 40 minutes is equal to 40/60 = 2/3 hours.
Now we can add the 2 hours and 2/3 hours together: 2 + 2/3 = 6/3 + 2/3 = 8/3 = 2 2/3.
Now we can multiply the total number of hours by Diana's average rate to find the total distance traveled: 30 mph * 2 2/3 hours = 60 + 20 = <<30*2+20=80>>80 miles. Answer: \boxed{80}.