Question 934569
Answer: No
Why, you ask?
Let's figure it out.
Let d = rt, with rate r in mph and t in hrs, then d is miles.
The time to travel the first mile is
(1) t1 = d/r or
(2) t1 = 1/15
Let the rate for the second mile be x, then the time for the second mile is
(3) t2 = 1/x
The average speed (rate) for the two miles is
(4) rave = d/t or
(5) rave = 2/(t1+t2) or
(6) rave = 2/(1/15 + 1/x)
We are asked if rave can be 30mph. Let's see. Can (6) be equal to 30?
(7) 30 = 2/(1/15 + 1/x) or
(8) 30 = 2/(x + 15)/(15x) or
(9) 30 = 30x/(x + 15) or
(10) 1 = x/(x + 15) or
(11) (x + 15) = x or
(12) 15 = 0
I don't recall that 15 = 0, do you?
So it is impossible. You need to travel the second mile in zero time. then we have in (5)
(13) rave = 2/(t1+t2) or 
(14) rave = 2/(1/15+0) or
(15) rave = 2/(1/15) or
(16) rave = 30
It means that we travel at an infinite rate to take zero seconds!
You're welcome.