Answer:
x =
, x = 1
Step-by-step explanation:
(a)
= x + 7 ( multiply both sides by 2 to clear the fraction )
4x - 1 = 2x + 14 ( subtract 2x from both sides )
2x - 1 = 14 ( add 1 to both sides )
2x = 15 ( divide both sides by 2 )
x = 
(b)
3x + 2 =
( multiply both sides by 3 to clear the fraction )
9x + 6 = 2x + 13 ( subtract 2x from both sides )
7x + 6 = 13 ( subtract 6 from both sides )
7x = 7 ( divide both sides by 7 )
x = 1
Answer:
(a) The standard deviation of your waiting time is 4.33 minutes.
(b) The probability that you will have to wait more than 2 standard deviations is 0.4227.
Step-by-step explanation:
Let <em>X</em> = the waiting time for the bus at the parking lot.
The random variable <em>X</em> is uniformly distributed with parameters <em>a</em> = 0 to <em>b</em> = 15.
The probability density function of <em>X</em> is given as follows:

(a)
The standard deviation of a Uniformly distributed random variable is given by:

Compute the standard deviation of the random variable <em>X</em> as follows:




Thus, the standard deviation of your waiting time is 4.33 minutes.
(b)
The value representing 2 standard deviations is:

Compute the value of P (X > 8.66) as follows:





Thus, the probability that you will have to wait more than 2 standard deviations is 0.4227.
I'm pretty sure the answer is b. because obviously 1.2 in is the least and the second least is the square root of 3.