First, you should consider that the gravity on that place is equal to 10 m/s².
Weight is equal to mass times gravity. (w = mg)
14700 = 10m
m = 1470 kg
Since the friction is numerically equal to the weight, you consider that the force responsible for allowing the car to make the turn safely is equal to the centripetal force (m.v²/r), that is, the friction.
Thus, using the second Newton's law, you can easily figure out the answer.
Fr = m.a
A is the rotational aceleration, which is equal to v²/r (Centripetal aceleration)
14700 = mv²/r
14700 = 1470.(26,1)² / r
Multiplying the denominator of the second member by the numerator of the first member, you will obtain:
14700r = 1470.(681,21)
14700r /1470 = 681,21
10r = 681,21
r = 68,121 m
That's it