Given:

Image distance, v = −d = −25 cm

Focal length, f = 10 cm

Object distance = u

When the image is formed at the near point or at the minimum distance of distinct vision, we get the maximum possible magnification.

Applying the lens formula we have:

…(1)

Where, f₀ = focal length of the objective lens

v₀ = Distance of image formation

u₀ = Distance of object from objective

Putting values in the equation (1) we get,

⇒

⇒ u = -50/7

⇒ u = -7.14 cm

Hence, the lens should be kept 7.14 cm away in order to view the squares distinctly.