The near point and far point of a person are 40 cm and 250 cm respectively. Determine the power of the lens he/she should use while reading a book kept at distance 25cm from the eye.

Correct option is C.
1.5D
If an object is placed at 25 cm from the correcting lens, it should produce the virtual image at 40 cm. Thus, u = −25cm, v = −40cm
1/f = 1/v − 1/u = 1/(-40cm) + 1/(25cm)
f = 200/3 cm = +20/3 m
Power of lens, P = 1/f = +1.5D