Answer
a). $P=-0.67D$
b). Near point is farther than 25cm
c). Old (50-60 years)
Work Step by Step
A man has far point of 150 cm.
a). $do=infinity$
$di=-150cm=-1.5m$
$P=\frac{1}{f}=\frac{1}{do}+\frac{1}{di}=\frac{1}{infinity}+\frac{1}{-1.5}=-0.67D$
b). Given he is able to read a newspaper at 25cm while wearing his contacts, then his near point is farther than his length as his eye is unable to focus near by objects.
Only for normal eye the near point is around of less than 25 cm.
c). As the person's both near and far point are not same as that of normal eyes hence the person must be old based on normal recession of near point.
