An older man not wearing any prescription glasses can only see clearly when obje

Question

An older man not wearing any prescription glasses can only see clearly when objects are between 49 cm and 151 cm away from his eye. An optometrist needs to make bifocal glasses for this man who will wear them 2.3 cm from his eye.
To see distant objects clearly using the upper part of bifocals, what power of glasses (in diopters) should be prescribed?
? Diopters
To read a book that is held 20 cm from his eye, what should the power of the lower part of the bifocals?
? Diopters

Power=1/focal length(meters) 1/focal length=1/object distance+1/image distance

I keep getting this wrong please help, please make sure answer is in diopters

Explanation / Answer

1/v-1/u=1/f
or 1/2.3-1/20=1/f

p=1/f=38.47 for lower part

and 42.81 for upper part.

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