Wind changes the ground result

A fictional sailplane model gives a horizontal airspeed of 60 knots and a constant downward sink speed of 2 knots relative to still air. It then adds a direct 15 knot headwind while assuming the same airspeed and sink remain unchanged. All speeds use compatible units, and the task asks for the glide ratio relative to the ground. A learner uses 60 divided by 2 and ignores the wind. Another changes the sink merely because the headwind has changed. The task asks what the stated model actually supports. No actual polar adjustment, speed-to-fly selection, terrain, arrival margin or landing permission is supplied. A correct answer keeps the horizontal wind component separate from the vertical descent assumption and avoids treating this fixed-speed comparison as an operational recommendation.