There are 327 official ports of entry in the United States. The Department of Homeland Security selects 15 ports of entry at random to be audited for compliance with screening procedures of incoming travelers through the primary and secondary vehicle and pedestrian lanes. what kind of sample is this?

Simple random sample

Step-by-step explanation:

Simple random sampling is a sampling technique where a smaller group of subjects are selected for study from a larger group. The subjects chosen are chosen at random, avoiding bias as each selected sample has an equal chance of selection.

This sampling technique is a basic technique used in science for blinded experiments or to carry out randomized control tests. The avoidance of bias in this sampling technique, creates a balanced subset, carrying the greatest potential for representing the larger group.  

As in this case, from a large sample of 327, 15 selections were made randomly, forming the subset of the larger group to be studied. Another example will be a study to identify the average number of minutes, spent by 1000 employees to get to work daily. To conduct this study, 250 of the 1000 employees could be selected at random and the number of minutes spent by each one analysed. The overall average gotten is then used to address the larger group as a whole.

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places

step-by-step explanation:

let pq = qr = rs = x, and xz = y and zu = z.

if the horizontal lines are parallel, then corresponding segments are in proportion:

substitute:

therefore 3 = y = z.

xu = y + z → xu = 3 + 3 = 6