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(Created page with "'''Answer: C''' The 20-year female survival probability <math>=e^{-20 \mu}</math> The 20-year male survival probability <math>=e^{-30 \mu}</math> We want 1 -year female survival <math>=e^{-\mu}</math> Suppose that there were <math>M</math> males and <math>3 M</math> females initially. After 20 years, there are expected to be <math>M e^{-30 \mu}</math> and <math>3 M e^{-20 \mu}</math> survivors, respectively. At that time we have: <math display = "block">\frac{3 M e^...") |
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<math display = "block">\frac{3 M e^{-20 \mu}}{M e^{-30 \mu}}=\frac{85}{15} \Rightarrow e^{10 \mu}=\frac{85}{45}=\frac{17}{9} \Rightarrow e^{-\mu}=\left(\frac{9}{17}\right)^{1 / 10}=0.938</math> | <math display = "block">\frac{3 M e^{-20 \mu}}{M e^{-30 \mu}}=\frac{85}{15} \Rightarrow e^{10 \mu}=\frac{85}{45}=\frac{17}{9} \Rightarrow e^{-\mu}=\left(\frac{9}{17}\right)^{1 / 10}=0.938</math> | ||
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Latest revision as of 02:34, 18 January 2024
Answer: C
The 20-year female survival probability [math]=e^{-20 \mu}[/math]
The 20-year male survival probability [math]=e^{-30 \mu}[/math]
We want 1 -year female survival [math]=e^{-\mu}[/math]
Suppose that there were [math]M[/math] males and [math]3 M[/math] females initially. After 20 years, there are expected to be [math]M e^{-30 \mu}[/math] and [math]3 M e^{-20 \mu}[/math] survivors, respectively. At that time we have:
[[math]]\frac{3 M e^{-20 \mu}}{M e^{-30 \mu}}=\frac{85}{15} \Rightarrow e^{10 \mu}=\frac{85}{45}=\frac{17}{9} \Rightarrow e^{-\mu}=\left(\frac{9}{17}\right)^{1 / 10}=0.938[[/math]]