Answer:
160 km
Step-by-step explanation:
g = 9.8 m/s^2, g' = 9.3 m/s^2
Let h be the height from ocean level.
Use the formula for acceleration due to gravity at height.
g' = g (1 - 2h/R)
The radius of earth is 6400 km
9.3 = 9.8 ( 1 - 2 H / R)
0.05 = 2 h/R
h = 0.05 × 6400 / 2 = 160 km