A certain distance is covered by a car at a uniform speed in $8$ hours. If the speed is reduced by $6\text{km/h}$, it will take $1$ hour more. What is the original speed of the car (in $\text{km/h}$)?

Let the original speed of the car be $s\text{km/h}$.
The original time taken = $8$ hours.
$$\text{Distance}=\text{Speed}\times \text{Time}=s\times 8=8s$$

When the speed is reduced by $6\text{km/h}$, the new speed $=s-6$.
The new time taken $=8+1=9$ hours.
$$\text{Distance}=(s-6)\times 9=9s-54$$

Since the distance covered in both cases is the same:
$$8s=9s-54$$
$$9s-8s=54$$
$$s=54\text{km/h}$$

Thus, the original speed of the car is $54\text{km/h}$.