57. An ordinary person can read a book, keeping it at a distance of 250 ∙ 10−3m from the eye, farsighted person this distance should be at least 800 ∙ 10−3m. Determine the optical power of the glasses necessary for a farsighted person to keep a book at the same distance from the eye as an ordinary person.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)