The distance between major cracks in a highway follows an exponential distribution with a mean of 20 miles. What is the standard deviation of the distance between two major cracks

20

Step-by-step explanation:

Let X be the exponentially distributed random variable with the given mean E(X)=20

#To find the standard deviation, we first determine lambda,:

We then find standard deviation using the formula:

Hence, the standard deviation of the distance between two major cracks is 20

5=812a+9+3

step 1: simplify both sides of the equation.

5=812a+9+3

5=(812a)+(9+3)(combine like terms)

5=812a+12

5=812a+12

step 2: flip the equation.

812a+12=5

step 3: subtract 12 from both sides.

812a+12−12=5−12

812a=−7

step 4: divide both sides by 812.

812a /812 = -7/812

a= -1/116

so the answer is

a=   -1/116