Answer:
Height will be 0.41 r
Step-by-step explanation:
We have given acceleration due to gravity at any height is 

Radius of the earth = r 
We know that acceleration due to gravity at any height is given by
 ----eqn 1
----eqn 1
And acceleration due to gravity at earth 
 ----eqn2
----eqn2
Dividing eqn 2 by eqn 1




h = 0.41 r