Given the following information, calculate the net glide distance for a single-engined aeroplane

operating under performance class B 

Aeroplane altitude: 10000 ft

 Terrain elevation: 500 ft 

Gross glide gradient: 10% 

TAS: 200 kt 

Headwind component: 20 kt 

1 NM = 6080 ft 

Still air distance = (height difference / net gradient) × 100

 Ground distance = Still Air Distance × (GS / TAS)

 A

12.5 NM

10.0 NM

C 13.4 NM

14.9 NM