The time between calls to a plumbing supply business is exponentially distributed with a mean time between calls of 13 minutes. (a) What is the probability that there are no calls within a 30-minute interval

P(X>30) = 1 - F(30) = 0.0995

Step-by-step explanation:

Let X be the exponential distributed random variable of time between the calls with the given mean of 13 minutes

E(X) = 13

As we have the continuous random variable (time), the distribution is

F(x) = 1 - e^(-λx)

Now we need to calculate the λ from the formula of exponential distribution which is

E(X) = 1/λ = 15

So, λ = 1/15

Now, we will calculate the probability that there are no call within 30 minutes time interval, It mean we need to find the probability when time is greater than 30 (X>30)

P (X>30) = 1 - F(30) = 1 - (1 - e^(-30*1/13)

P (X>30) = e^(-30/13) = e^(-2.3) = 0.0995

P(X>30) = 0.0995

a. 74 degrees

step-by-step explanation:

because the lines through the side and the box in the corners shows that these are congruent triangles and since they are mirrored the 37 degrees is also mirrored so the answer is 37 * 2 which is 74.

y = 2x

step-by-step explanation:

if you divide each number in the sequence, you'll see that they all have a multiple factor of 2. each number in the series, and any other numbers which may continue, will be multiplied by 2. therefore, y is the next number in the sequence, and x is the current one, so, our formula will be y = 2x.