Forahigh-riskdriver,thetimeindaysbetweenthe beginning of a year and an accident has an exponential pdf. Suppose an insurance company believes the probability that such a driver will be involved in an accident in the first forty days is 0.25. What is the probability that such a driver will be involved in an accident during the first seventy-five days of the year?

Respuesta :

Answer:

The probability that such a driver will be involved in an accident during the first seventy-five days of the year is 0.408

Step-by-step explanation:

Consider the provide information.

The probability that such a driver will be involved in an accident in the first forty days is 0.25.

Therefore, [tex]P(X\leq 40)=0.25[/tex]

Where is X represents the random variable that shows time between beginning of a year and an accident.

X is the exponential distribution with λ as a parameter.

[tex]P(X\leq x)=1-e^{-\lambda x}, x\geq 0[/tex]

Therefore,

[tex]P(X\leq 40)=1-e^{-40\lambda}[/tex]

[tex]1-e^{-40\lambda}=0.25[/tex]

[tex]e^{-40\lambda}=0.75\\-40\lambda=ln(0.75)\\\lambda=0.00719\approx0.007192[/tex]

Now we want the probability that a driver will be involved in an accident during the first seventy five days.

[tex]P(X\leq 75)=1-e^{-75\times 0.0072}=0.408[/tex]

Hence, the probability that such a driver will be involved in an accident during the first seventy-five days of the year is 0.408