Answer:
82.4 cm
Step-by-step explanation:
The object and screen are kept fixed ie the distance between them is fixed and by displacing lens between them images are formed on the screen . In the first case let u be the object distance and v be the image distance
then ,
u + v = 184 cm
In the second case of image formation , v becomes u and u becomes v only then image formation in the second case is possible.
The difference between two object distance ie( v - u ) is the distance by which lens is moved so
v - u = 82.4 cm