Stuck on Problem....

The centripetal force required to keep the car from skidding is given by

$$F=m\frac{v^2}{r}$$

where m is the mass of the car, v is it's speed and r is the curve radius.

The frictional force is

$$F=\mu mg$$

where μ is the coefficient of friction and g is gravitational acceleration.

So equating these two forces we have:

$$\frac{v^2}{r}=\mu g\\\\ v=\sqrt{\mu gr}$$

I'll let you put in the numbers.