Question

To expel hot air out of the kitchen Ahas an exhaust fan fitted on the window of her kitchen andBhas a similar exhaust fan fitted on the wall near the celling of her kitchen which of the exhaust fan will expell the hot air more effectively explain why

Answer 1

This is a very simple logic.

See, the hot air rises more than the cold air since it is lighter. This is called convection. You can see this phenomenon near sea shores.
The hot air will be expelled readily near the ceiling because the hot air is concentrated there