Given data:
* The speed of the bus is 10 mph.
* The speed of the person in the bus is 2 mph.
Solution:
As the person and the bus are moving in the same direction, thus, the speed of the person with rest to the rest frame is the sum of the speed of the bus and speed of the person in the bus.
The speed of the person with respect to the lecture hall (rest) is,
![\begin{gathered} v=10\text{ mph + 2 mph} \\ v=12\text{ mph} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/ferdhr1akjkjyp4y2x3ij6xhnn1wj7yvh7.png)
Hence, the speed of the person with respect to the lecture hall is 12 mph.