(a) For a normal eye, the near point is at 25 cm and the far point is at infinity. The given person cannot see object clearly either closer to the eye or-far away from the eye. So he is suffering from both myopia and hypermetropia.
(b) A bi-focal lens consisting of a concave lens and convex lens of suitable focal lengths will be required to correct the defects and to increase his range or vision from 25 cm to infinity. In a bi-focallens,theupperhalfofthelensisconcave which corrects distant vision and the lower half is convex which corrects near vision.