HiSET: Math : Apply concepts of density in modeling situations

Study concepts, example questions & explanations for HiSET: Math

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Example Questions

Example Question #1 : Apply Concepts Of Density In Modeling Situations

A farmer has to make a square pen to hold chickens. If each chicken has to have  of area to roam and there are  chickens total, what is the length of the amount of fencing required to pen in the chickens?

Possible Answers:

Correct answer:

Explanation:

A square has area formula

 

The total area required for the chickens will be

since each chicken requires  of space and there are  chickens.

Thus, we have

for the length of our chicken fence.

Since there are four sides of a square and each side has a length of 5, the total length of fence required is

.

Example Question #1 : Apply Concepts Of Density In Modeling Situations

Census

Source: United States Census Bureau

The average population density of a geographic area is defined to be the average number of residents per square mile.

Above is a table with the land areas and populations of five states.Which state among the five has the greatest population density?

Possible Answers:

Tennessee

Mississippi

Kentucky

Arkansas

Alabama

Correct answer:

Tennessee

Explanation:

For each state, divide the population by the land area. We can round each figure to the nearest whole for simplicity's sake.

Alabama:

 persons per square mile.

Arkansas:

 persons per square mile.

Kentucky:

 persons per square mile.

Mississippi:

 persons per square mile.

Tennessee:

 persons per square mile.

Tennessee has the greatest population density among the five states. 

Example Question #1 : Apply Concepts Of Density In Modeling Situations

Census

Source: United States Census Bureau

The average population density of a geographic area is defined to be the average number of residents per square mile.

Above is a table with the population densities and the land areas of five states. Of the five, which state has the greatest population?

Possible Answers:

North Dakota

Vermont

South Dakota

Alaska

Wyoming 

Correct answer:

South Dakota

Explanation:

Multiply the population density of each state by its corresponding area to get an estimate of the population (round to the nearest thousand for simplicity's sake):

Alaska:

North Dakota:

South Dakota:

Vermont:

Wyoming:

Of the five states, South Dakota is the most populous.

Example Question #1 : Apply Concepts Of Density In Modeling Situations

County 1

The average population density of a geographic area is defined to be the average number of residents per square mile.

Above is the map of a county whose population is about 120,000. Which of the following is the best estimate of the average population density?

Possible Answers:

100 persons per square mile

200 persons per square mile

150 persons per square mile

50 persons per square mile

250 persons per square mile

Correct answer:

100 persons per square mile

Explanation:

The county is in the shape of a trapezoid with bases of length  and , and with height . Its area in square miles can be found by substituting in the formula for the area of a trapezoid:

 square miles

Divide the population by this area to obtain an estimate of the population density:

 persons per square mile.

Of the given choices, 100 persons per square mile comes closest.

Example Question #181 : Hi Set: High School Equivalency Test: Math

The graphic below shows a blueprint for a swimming pool.

Swimming pool dimensions

If the pool is going to be 66 inches deep, how many cubic feet of water will it be able to hold? (1 ft = 12 in)

Possible Answers:

Correct answer:

Explanation:

Notice that the outer dimensions of the blueprint are the dimensions for the entire pool, including the concrete, while the inner dimensions are for the part of the pool that will be filled with water. Therefore, we want to focus on just the inner dimensions.

Notice that the depth is given in inches, while the dimensions are in feet. Convert 66 inches to feet by dividing 66 by 12, since 12 inches makes a foot:

The inch units cancel out and leave us with just the feet units. 66 in is 5.5 ft.

Now we have all of the information we need to solve for the volume of the pool. The pool is a rectangular prism, and the formula for volume of a rectangular prism is

(In this case, the "height" of the swimming pool is its depth.)

The blueprint shows that the pool is 40 ft long and 30 ft wide. Plugging in the measurements from the problem, we get

Multiplying this out, we get .

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