Answer
a. 4.17.
b. 4.84 cm.
Work Step by Step
a. When the object is at the focal point, $M=\frac{25.0 cm}{f}$. This calculation assumes the near point is 25.0 cm from the eye.
$$M=\frac{25.0 cm}{6.00cm}=4.17$$
b. Use the lens equation.
$$\frac{1}{s}+\frac{1}{s’}=\frac{1}{f}$$
$$\frac{1}{s}+\frac{1}{-25.0cm}=\frac{1}{6.00cm}$$
$$s=4.84cm$$
