Question
Haimi drove a car from West Union, Minnesota, through North Dakota, to Miles City, Montana. The total distance she traveled through each state is shown in the figure.
The distance \(d\), in miles, Haimi drove as a function of the time \(t\), in hours, since she started driving is modeled by the equation \(d\) = 60\(t\).
According to the model, what distance, in miles, had Haimi driven 3 hours after she started driving?
A) 20
B) 60
C) 120
D) 180
Answer/Explanation
Ans: D
Question
What interval represents all values of \(t\) during which Haimi drove in North Dakota?
- 2 10
- 2 8
- 0 8
- 0 2
Answer/Explanation
Ans: B
Question
The graph shows the number of algae cells grown during an experiment, in millions of cells per milliliter (mL) of water, \(d\) days after the start of an experiment. Between which two days was the growth rate, in millions of cells per mL of water per day, of the algae the greatest?
- Day 4 and day 5
- Day 5 and day 6
- Day 7 and day 8
- Day 9 and day 10
Answer/Explanation
Ans: B
Question
When a buffet restaurant charges \($\)12.00 per meal, the number of meals it sells per day is 400. For each \($\)0.50 increase to the price per meal, the number of meals sold per day decreases by 10. What is the price per meal that results in the greatest sales, in dollars, from meals each day?
- $16.00
- $20.00
- $24.00
- $28.00
Answer/Explanation
Ans: A
Question
When a buffet restaurant charges \($\)12.00 per meal, the number of meals it sells per day is 400. For each \($\)0.50 increase to the price per meal, the number of meals sold per day decreases by 10. What is the price per meal that results in the greatest sales, in dollars, from meals each day?
- $16.00
- $20.00
- $24.00
- $28.00
Answer/Explanation
Ans: A
Question
The number of books in a library increased by 30% from 2002 to 2014. There were \(x\) books in the library in 2002. Which expression represents the number of books in the library in 2014 in terms of \(x\) ?
- 130\(x\)
- 30\(x\)
- 1.3\(x\)
- 0.3\(x\)
Answer/Explanation
Ans: C
Question
The half-life of the radioactive isotope iodine-131 is approximately 8 days, which means that at the end of each 8-day time interval only half of the mass of the isotope that was present at the beginning of the time interval remains. Which of the following best describes how the amount of iodine-131 changes over time?
- It increases linearly.
- It decreases linearly.
- It increases exponentially.
- It decreases exponentially.
Answer/Explanation
Ans: D
Question
A psychologist conducting a memory experiment provided participants with a list of three-letter sequences. Immediately after the experiment, the participants remembered 100% of the sequences. The psychologist found that the percentage of sequences the participants remembered decreased by 30% for every 3-second interval that passed. Which function best models this situation, where \(P\) is the percentage of sequences the participants remembered, and \(t\) is the time, in seconds, that passed?
- \(P\)(\(t\))= 100(0.30)3t
- \(P\)(\(t\))= 100(0.30)t
- \(P\)(\(t\))=100(0.70)t/3
- \(P\)(\(t\))=100(0.70)t
Answer/Explanation
Ans: C