The radii of the earth and the moon are in the ratio 10 : 1 while acceleration due to gravity on the earth’s surface and moon’s surface are in the ratio 6 : 1. The ratio of escape velocities from earth’s surface to that of moon surface is
6 : 1
1.66 : 1
7.74 : 1
                
                  As we learnt in
Acceleration due to gravity (g) -
Force extended by earth on a body is gravity.
Formula:    
 gravity
 density of earth
 Radius of earth
- wherein
It's average value is  on the surface of earth

 Escape velocity = 
Option 1)
This is incorrect option
Option 2)
6 : 1
This is incorrect option
Option 3)
1.66 : 1
This is incorrect option
Option 4)
7.74 : 1
This is correct option