Answer:
[tex]P(20<X<40)=0.24[/tex]
Step-by-step explanation:
Given that our variable is exponentially distributed with [tex]\mu=38.3 \ mins[/tex], let X be the time to travel to work defined as:
[tex]f(X)=\frac{1}{\mu}e^-^x^/^u;\ \ \ \ \ \ \ \ \mu=38.3\\f(X)=\frac{1}{38.3}e^-^x^/^3^8^.^3[/tex]
To find [tex]P(20<X<40)[/tex];
[tex]P(20<X<40)=(1-e^-^4^0^/^3^8^.^3)-(1-e^-^2^0^/^3^8^.^3)\\=-e^-^1^.^0^4+-e^-^0^.^5^2^2\\=0.24[/tex]
The probability that it takes between 20 to 40 minutes to get to work is 0.24