Question 1009848
Let's call the rate of the plane, r.  thus the rate of the car is r - 90.
We know that in general rt = d, or t = d/r.
Since the times are equal, we can then set up a proportion to solve...
{{{980/r = 350/(r-90)}}}
Now cross-multiply and solve
980(r-90) = 350r
980r - 88200 = 350r
-88200 = -630r
r = 140 mph