A person is to be fitted with bifocals. She can see clearly when the object is between 43 cm and 1.5 m from the eye.

A person is to be fitted with bifocals. Shecan see clearly when the object is between43 cm and 1.5 m from the eye. The upperportions of the bifocals should be designed toenable her to see distant objects clearly. What power should they have? Answer in units of diopters.