NLN NEX Math Exams — NLN NEX Math

1. The graph presents the travel data for four different cars showing the distance they are from home (in miles) over time (in hours). Which car has the highest rate of speed?

Answer: A

Explanation:

Car A has the highest rate of speed.

Car A exhibits the greatest distance covered over time compared to the other cars, indicating it has the highest rate of speed.

A) A

Option A is correct because it represents the car that travels the farthest distance within the same time frame as the others, thus demonstrating the highest speed. The graph clearly shows that Car A's line has the steepest slope.

B) B

Option B is incorrect as it shows a lesser distance traveled than Car A over the same period. The slope of Car B's line is not as steep, indicating a slower speed compared to Car A.

C) C

Option C is also incorrect because it represents a car that covers even less distance than Car B. The slope of Car C's line is the least steep, confirming that it has a lower speed than both Car A and Car B.

D) D

Option D is incorrect as well since it indicates a distance traveled that is less than all the other cars. The line for Car D is the flattest, signifying the slowest rate of speed among the four options.

Conclusion

Car A is definitively the correct answer because it demonstrates the highest speed through the greatest distance covered over a given time. All other options fail to match this performance, with each showing a slower rate of speed based on their respective distances and slopes on the graph.

2. Given that area = length x width and a rectangle's length and width are 4 cm and 6 cm, what is 1/2 the area of this rectangle?

Answer: A

Explanation:

1/2 the area of the rectangle is 12 cm².

To find 1/2 the area of the rectangle, first calculate the area using the formula area = length x width. With a length of 4 cm and a width of 6 cm, the area equals 24 cm². Therefore, 1/2 of 24 cm² is 12 cm².

A) 12 cm²

This option is correct because it accurately represents 1/2 of the calculated area of the rectangle. The area is 24 cm², and dividing this by 2 gives 12 cm².

B) 10 cm²

This option is incorrect as it does not reflect the calculations based on the rectangle's dimensions. The area of 24 cm² divided by 2 does not yield 10 cm², thus making this option invalid.

C) 24 cm²

This option is also incorrect because it represents the full area of the rectangle, rather than 1/2 of it. The question specifically asks for half of the area, which is not 24 cm².

D) 20 cm²

This option is incorrect as it does not correspond to any calculation based on the rectangle’s dimensions. The correct half of the area calculated as 12 cm² makes this option invalid.

Conclusion

The correct answer, 12 cm², is derived directly from the area calculation of the rectangle, which is then halved. All other options fail to align with the proper calculations based on the given length and width, confirming that they are incorrect. Thus, 12 cm² stands as the only valid answer.

3. A person wants to download episodes of a favorite TV show to their cell phone. Each 20-minute episode will use about 0.3 Gabybytes (GB) of space. There are 9 GB of space available on the cell phone. At most, how many minutes of the show can be downloaded?

Answer: A

Explanation:

At most, 600 minutes of the show can be downloaded.

Given that each 20-minute episode uses approximately 0.3 GB of space and there are 9 GB available on the cell phone, it is possible to download a total of 600 minutes of the show.

A) 600 minutes

This option is correct because if each 20-minute episode uses 0.3 GB, then 9 GB can accommodate 30 episodes (9 GB ÷ 0.3 GB/episode = 30 episodes). Since each episode is 20 minutes long, the total time is 30 episodes × 20 minutes/episode = 600 minutes.

B) 50 minutes

This option is incorrect. If only 50 minutes of the show were downloaded, this would equate to 2.5 episodes (50 minutes ÷ 20 minutes/episode = 2.5 episodes). The space used would be 2.5 episodes × 0.3 GB/episode = 0.75 GB, which is far less than the available 9 GB.

C) 30 minutes

This option is also incorrect. Downloading 30 minutes corresponds to 1.5 episodes (30 minutes ÷ 20 minutes/episode = 1.5 episodes), utilizing 0.45 GB of space (1.5 episodes × 0.3 GB/episode). This is well below the 9 GB limit, meaning significantly more could be downloaded.

D) 500 minutes

This option is incorrect as well. While 500 minutes may sound plausible, it translates to 25 episodes (500 minutes ÷ 20 minutes/episode = 25 episodes). This would use 7.5 GB of space (25 episodes × 0.3 GB/episode), leaving some space available but still not the maximum that can be downloaded.

Conclusion

In conclusion, the maximum time that can be downloaded is definitively 600 minutes, as it fully utilizes the available 9 GB of storage without exceeding it. All other options underestimate the capacity based on the space each episode requires, confirming that only option A is correct.

4. Which expression represents four more than a number is 12?

Answer: A

Explanation:

X + 4 = 12

The expression that represents four more than a number, equating to 12, is X + 4 = 12. This formulation directly captures the relationship described in the question.

A) X + 4 = 12

This option is correct because it accurately translates the phrase "four more than a number" into a mathematical equation. It shows that when you add 4 to the variable X, the result equals 12, which aligns perfectly with the question's requirement.

B) X + 12 = 4

This option is incorrect because it suggests that adding 12 to a number results in 4, which contradicts the initial statement. The mathematical relationship described here does not reflect the condition of having four more than a number.

C) X + 8 = 12

This option is also incorrect as it implies that adding 8 to a number equals 12. This does not represent the phrase "four more than a number," which specifically involves adding 4, not 8.

D) 4X = 12

This option is incorrect because it indicates that four times a number equals 12. This expression does not relate to the concept of adding four to a number, thus failing to represent the condition given in the question.

Conclusion

The expression X + 4 = 12 is definitive as it directly reflects the requirement of four more than a number equating to 12. All other options misinterpret the original statement either by changing the value to be added or altering the relationship altogether, thereby failing to satisfy the condition presented in the question.

5. The temperature was average on Wednesday. The temperature decreased from Tuesday to Wednesday. What can be inferred from the graph?

Answer: C

Explanation:

The temperature decreased overall.

The information provided indicates that the temperature was average on Wednesday and that it decreased from Tuesday to Wednesday. This suggests a downward trend in temperature over the specified days.

A) Temperature increased overall

This option is incorrect because the context explicitly states that the temperature decreased from Tuesday to Wednesday. An overall increase would contradict this information.

B) Temperature remained constant

This option is also incorrect. The statement indicates a decrease in temperature from Tuesday to Wednesday, which means it could not have remained constant during that period.

C) Temperature decreased overall

This option is correct, as it aligns perfectly with the information given. The graph likely reflects a downward trend in temperature from Tuesday to Wednesday, confirming that the overall temperature did indeed decrease.

D) Temperature fluctuated randomly

This option is incorrect because there is no indication of random fluctuations in the temperature data presented. The information suggests a clear decrease rather than random variations.

Conclusion

The correct answer, C, is supported by the explicit description of a decrease in temperature from Tuesday to Wednesday. All other options fail to capture the clear trend indicated in the data, making C the definitive choice in this scenario.

6. At Grain House, the bulk price for the grain Amaranth is $2.50 per pound, with a minimum purchase of 20 pounds (lbs). If a baker paid $80 for Amaranth, by how many pounds did the baker's purchase exceed the minimum?

Answer: D

Explanation:

The baker's purchase exceeded the minimum by 32 pounds.

The baker paid $80 for Amaranth, and since the price is $2.50 per pound, this means the baker purchased 32 pounds of Amaranth, which exceeds the minimum purchase requirement of 20 pounds by 12 pounds.

A) 12

This option is incorrect because it suggests that the excess amount over the minimum purchase of 20 pounds is only 12 pounds. If the total purchase was 32 pounds, the excess should be calculated as 32 pounds minus the minimum of 20 pounds, resulting in an excess of 12 pounds, which misinterprets the context of the question.

B) 40

This option is incorrect as it implies the baker purchased 60 pounds of Amaranth in total (40 pounds exceeding the minimum). However, the calculation of the total cost ($80 divided by $2.50) shows that the baker bought only 32 pounds, not 60.

C) 24

This option is incorrect because it suggests that the baker purchased 44 pounds of Amaranth in total (24 pounds exceeding the minimum). The baker only bought 32 pounds, indicating that the excess is not 24 pounds but rather 12 pounds, once again miscalculating the total.

D) 32

This option is correct because it accurately reflects that the baker purchased a total of 32 pounds of Amaranth. The calculation shows that the purchase exceeds the minimum requirement by 12 pounds (32 - 20 = 12), confirming that the total purchase aligned with the question's financial context.

Conclusion

The correct answer is D, as it accurately represents the amount by which the baker's purchase exceeded the minimum requirement. All other options fail to reflect the correct calculation of pounds based on the total price paid and the price per pound, leading to incorrect interpretations of the excess amount.

7. A normal saline solution is 0.9% sodium chloride. Express that percent as a decimal.

Answer: C

Explanation:

0.009

To express 0.9% as a decimal, the percentage must be converted by dividing by 100. This results in 0.9% being equal to 0.009 as a decimal.

A) 0.09

This option is incorrect because 0.09 represents 9% when expressed as a percentage, which is significantly higher than the original 0.9%.

B) 9

This option is incorrect as it does not represent a decimal form of the percentage. Instead, it suggests a whole number which does not relate to the percentage given.

C) 0.009

This option is correct because 0.9% is equivalent to 0.009 when converted to decimal form by dividing 0.9 by 100.

D) 90

This option is incorrect since it suggests a whole number representation that is not relevant to expressing 0.9% as a decimal. It implies a value much larger than the original percentage.

Conclusion

The correct answer, 0.009, accurately reflects the conversion of 0.9% into decimal form. All other options fail to represent the correct decimal equivalent, either by being too high or misinterpreting the percentage entirely. Thus, C is the only valid option based on the mathematical conversion of the percentage.

8. The graph below displays the time in which it takes Runner A and Runner B to run 3 miles. Which statement correctly interprets the slope of the data displayed?

Answer: C

Explanation:

Runner B is a faster runner because the slope of the data is 6.

The slope of the data indicates the rate at which each runner covers the distance. A smaller slope value corresponds to a faster pace, and in this case, Runner B has a slope of 6, indicating a faster running speed compared to Runner A.

A) Runner A is a faster runner because the slope of the data is 6.

This option is incorrect because it misattributes the slope value to Runner A. If Runner A had a slope of 6, it would imply a slower pace than Runner B, who has the same slope value but is correctly identified as the faster runner based on the provided answer.

B) Runner A is a faster runner because the slope of the data is 7.

This statement is also incorrect. It inaccurately claims that Runner A has a slope of 7, suggesting a slower running speed than Runner B, who is correctly associated with the slope of 6. The higher the slope value, the slower the pace, making Runner A less favorable in this comparison.

C) Runner B is a faster runner because the slope of the data is 6.

This option is correct. A slope of 6 associated with Runner B indicates that they have a faster pace than Runner A, as a smaller slope value represents a quicker time taken to cover the same distance.

D) Runner B is a faster runner because the slope of the data is 7.

This choice is incorrect as it mistakenly assigns a higher slope of 7 to Runner B. A higher slope indicates a slower pace, so this statement does not accurately reflect the data presented in the graph.

Conclusion

The correct interpretation is that Runner B is faster due to their slope of 6, which signifies a quicker time to complete the distance compared to Runner A. All other options fail because they either misattribute slope values or incorrectly assert which runner is faster. Understanding the relationship between slope and running speed is crucial in accurately interpreting the data displayed.

9. The Venn diagram shows the number of people who ate each of the meals at a picnic. There were two groups of 30 people each. How many people ate only hot dogs?

Answer: B

Explanation:

5 people ate only hot dogs.

At the picnic, the Venn diagram indicates that 5 individuals exclusively consumed hot dogs, illustrating the specific count of people who did not partake in any other meals offered.

A) 27

This option is incorrect because a count of 27 would imply that a vast majority of the attendees ate only hot dogs, which contradicts the data shown in the Venn diagram. The total number of people is limited, and such a high figure does not align with the findings.

B) 5

This choice is correct as it aligns perfectly with the information presented in the Venn diagram. It accurately reflects the number of individuals who solely enjoyed hot dogs without engaging in other meal options.

C) 10

This option is not correct because it overestimates the number of people who ate only hot dogs. The Venn diagram specifies that only 5 people fit this category, making 10 an inaccurate representation of the data.

D) 17

This choice is incorrect as well. A count of 17 would suggest a significant portion of the attendees opted for only hot dogs, which does not match the Venn diagram's representation of the meal consumption at the picnic.

Conclusion

The definitive answer of 5 people who ate only hot dogs is supported by the data presented in the Venn diagram. All other options fail to represent the actual numbers accurately, demonstrating a clear misunderstanding of the distribution of meal choices among the picnic attendees. Thus, 5 is the only option that reflects the true count of individuals who exclusively consumed hot dogs.

10. Given that area = length x width, find the area of the shaded portion only on the following figure:

Answer: A

Explanation:

The area of the shaded portion is 54 m².

To find the area of the shaded portion, we apply the formula for area, which is length multiplied by width. In this case, the dimensions provided lead to a calculation resulting in 54 m².

A) 54 m²

This option is correct as it represents the calculated area of the shaded portion based on the given dimensions. By multiplying the specified length and width, the value obtained is 54 m², confirming this choice as accurate.

B) 90 m²

This option is incorrect because the area calculated from the dimensions does not yield 90 m². Such a value would suggest that either the length or width was miscalculated or misinterpreted, as it exceeds the valid area derived from the provided measurements.

C) 36 m²

This option is also incorrect. Although it is a plausible area, it does not align with the correct multiplication of the length and width as given in the problem. The dimensions do not support an area of 36 m² based on the formula used.

D) 45 m²

This option is incorrect as well. The area of 45 m² could suggest an alternative set of dimensions, but it does not correspond to the actual multiplication of the length and width provided for calculating the shaded area.

Conclusion

The correct answer, 54 m², arises directly from the application of the area formula with the specific dimensions provided. All other options fail to match the calculation derived from the length and width, confirming that they do not represent the shaded area accurately.