Question 128275
Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r

amount of time it takes first plane to arrive in Miami=(d/r)=2240/280=8 hr.
This means that first plane gets into Miami at 9:30pm and we are told that the second plane is scheduled to land at 9:15pm.  So, the second plane has to make the trip in (9:15-2:15)or 7 hrs.  Now we can easily calculate the rate of the second plane:

Rate of second plane=(d/t)=2240/7=320 mph

Hope this helps---ptaylor