The answer is 11 m/s.
As you know, an object that's travelling along a circular motion is experiencing an outward force called the centrifugal force.
In order for a car to be able to turn around a curve of radius
That is, the force of friction acts to prevent the car from sliding off the road, i.e. it counteracts the centrifugal force.
Mathematically, this is witten like this
This means that the velocity of the car will be
I'll leave the answer rounded to two sig figs, despite the fact that you only gave one sig fig for the radius of the curve and for the coefficient of friction
The maximum speed the car can have without skidding is 10.85 m/s or 39 km/hr
As the road is level, the only forces are the "reaction to the centripetal force" (directed outwards) and the frictional force (directed inwards).
We take the limiting case when the forces balance as only if the reaction is larger the car skids.
Reaction to centripetal Force
Force due to friction
(independent of mass of vehicle)