An aeroplane leaves a point on latitude 54'S at 10a.m it flies due south at a steady speed of800kmh.a.what is it's latitude at mid day?b.At what time does it pass over the South Pole

so, it flies for 2 hours, covering 1600 km

Do you know how many km/°lat ?
If so, divide to get ° covered.
Now -- how many more hours to cover the remaining ° ?
Add that to noon o'clock.