Excluding stoppage, the speed of bus is $66\text{km/hr}$ and including stoppage it is $55\text{km/hr}$. How many minutes does the bus stop per hour?

The formula to find the stoppage time per hour is given by:
$$\text{Stoppage time per hour}=\frac{\text{Speed excluding stoppage}-\text{Speed including stoppage}}{\text{Speed excluding stoppage}}\times 60\text{minutes}$$

Given:

* Speed excluding stoppage = $66\text{km/hr}$
* Speed including stoppage = $55\text{km/hr}$

Substituting the values into the formula:

$$\text{Stoppage time per hour}=\frac{66-55}{66}\times 60$$

$$\text{Stoppage time per hour}=\frac{11}{66}\times 60=\frac{1}{6}\times 60=10\text{minutes}$$

Therefore, the bus stops for $10$ minutes per hour.