M_{\text{tot}} = M_{\text{obj}} M_{\text{eye}} 입니다.

1. M_{\text{eye}} : M_{\text{eye}} = \dfrac{25~\text{cm}}{f_{\text{eye}}} = \dfrac{25}{2.5} = 10

2. q_{\text{obj}} : q_{\text{obj}} = L - f_{\text{eye}} = 23.0 - 2.50 = 20.5~\text{cm}

3. p_{\text{obj}} : \dfrac{1}{p_{\text{obj}}} = \dfrac{1}{0.400} - \dfrac{1}{20.5} \approx 2.451\;\Rightarrow\;p_{\text{obj}} \approx 0.408~\text{cm}

4. M_{\text{tot}} : M_{\text{tot}} \approx \left( \dfrac{20.5}{0.408} \right) \times 10 \approx 50.2 \times 10 \approx 502~\text{배}