## College Physics (7th Edition)

a) $1.75X$ b) $1.3X$
a). For a person with near point at 25cm, $m=1+\frac{25}{f}$ $P=\frac{1}{f}$ or, $f=\frac{1}{P}=\frac{1}{3}=0.33m=33.3cm$ $m=1+\frac{25}{33.3}=1.75X$ b). For a person with near point at 10cm, $m=1+\frac{10}{f}=1+\frac{10}{33.3}=1.3X$