Lift over drag (L/D) ratio determines the gliding range. The Glide ratio of an aircraft is the distance of forward travel divided by the altitude lost in that distance.

If L/D = 30 => Aircraft will fly 30 units over the ground per every unit down (assuming no wind).
Ground distance = 60 km = 60 000 m

• Therefore, with a ground distance of 60 000 m (60 km) and L/D of 1:30, we get the following equation:
  1 / 30 = x / 60 000
  x = 2 000 m
• Since the question asks for minimum height (not altitude), the correct option is 2 000 m.

Note: Altitude - The vertical distance of an object measured from mean sea level.
Height -The vertical distance of a level, a point, or an object considered as a point, measured from a specified datum.

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