excans:F274ac1813: Difference between revisions
From Stochiki
No edit summary |
No edit summary |
||
Line 12: | Line 12: | ||
{{soacopyright | 2024 }} | {{soacopyright | 2024 }} | ||
{{soacopyright|2024}} | |||
{{soacopyright|2024}} | {{soacopyright|2024}} | ||
{{soacopyright|2024}} | {{soacopyright|2024}} |
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]]