Answer:
a) 50.34% probability that the arrival time between customers will be 7 minutes or less.
b) 24.42% probability that the arrival time between customers will be between 3 and 7 minutes
Explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:
![f(x) = \mu e^(-\mu x)](https://img.qammunity.org/2021/formulas/mathematics/college/dam9hldn5eii4iphfl0p3y8th5zcdwsk06.png)
In which
is the decay parameter.
The probability that x is lower or equal to a is given by:
![P(X \leq x) = \int\limits^a_0 {f(x)} \, dx](https://img.qammunity.org/2021/formulas/mathematics/college/e3wq4vesqfh4k7cpas1osi6h6zh6fbaxh9.png)
Which has the following solution:
![P(X \leq x) = 1 - e^(-\mu x)](https://img.qammunity.org/2021/formulas/mathematics/college/a6ylb0hy2ltvg7lomfj0epinygu41sl4cu.png)
The probability of finding a value higher than x is:
![P(X > x) = 1 - P(X \leq x) = 1 - (1 - e^(-\mu x)) = e^(-\mu x)](https://img.qammunity.org/2021/formulas/mathematics/college/ax8vjmdslhxv470f2ipkus8ouq1o1ulkcv.png)
Mean of 10 minutes:
This means that
![m = 10, \mu = (1)/(10) = 0.1](https://img.qammunity.org/2021/formulas/mathematics/college/d73ou1e0leknoyqp0b8z6fr276hyudsebc.png)
A. What is the probability that the arrival time between customers will be 7 minutes or less?
![P(X \leq x) = 1 - e^(-\mu x)](https://img.qammunity.org/2021/formulas/mathematics/college/a6ylb0hy2ltvg7lomfj0epinygu41sl4cu.png)
![P(X \leq 7) = 1 - e^(-0.1*7) = 0.5034](https://img.qammunity.org/2021/formulas/mathematics/college/svoizljoyb431oxltia8osnux5i5jzywrg.png)
50.34% probability that the arrival time between customers will be 7 minutes or less.
B. What is the probability that the arrival time between customers will be between 3 and 7 minutes?
![P(3 \leq X \leq 7) = P(X \leq 7) - P(X \leq 3)](https://img.qammunity.org/2021/formulas/mathematics/college/aeaz5wug170rxx89u6ybl2kn05ptf7sf7p.png)
![P(X \leq x) = 1 - e^(-\mu x)](https://img.qammunity.org/2021/formulas/mathematics/college/a6ylb0hy2ltvg7lomfj0epinygu41sl4cu.png)
![P(X \leq 7) = 1 - e^(-0.1*7) = 0.5034](https://img.qammunity.org/2021/formulas/mathematics/college/svoizljoyb431oxltia8osnux5i5jzywrg.png)
![P(X \leq 3) = 1 - e^(-0.1*3) = 0.2592](https://img.qammunity.org/2021/formulas/mathematics/college/6r126lagn7aumtnqz4pb151j8iije0twd1.png)
![P(3 \leq X \leq 7) = P(X \leq 7) - P(X \leq 3) = 0.5034 - 0.2592 = 0.2442](https://img.qammunity.org/2021/formulas/mathematics/college/1azmqfz3junxl98vvtie3yd8iop7nccwb2.png)
24.42% probability that the arrival time between customers will be between 3 and 7 minutes