Assuming the person wears contacts, what power of contact lens must be used to correct the vision of a farsighted person whose near point is 45.0 m? (no one would actually wear these as contacts)

1.78 D

Explanation:

v = 25 cm

u = 45 cm

use lens equation

1 / f = 1 / v - 1 / u

1 / f  = 1 / 25 - 1 / 45

1 / f = (45 - 25) / 25 x 45

1 / f = 20 / 25 x 45

Power, P = 100 / f (m)  

P = 2000 / 25 x 45 = 1.78 D

Thus, the power of lens is 1.78 D.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)