In June, a family used 3,500 gallons of water. In July, they used 15% more water.

Select all the expressions that represent the number of gallons of water the family used in July.

Han’s summer job paid him $4,500 last summer. This summer, he will get a 25% pay increase from the company.

Write two different expressions that could be used to find his new salary, in dollars.

1. Military veterans receive a 25% discount on movie tickets that normally cost \$16. Explain why \(16 (0.75)\) represents the cost of a ticket using the discount.
2. A new car costs \$15,000, and the sales tax is 8%. Explain why \(15,\!000(1.08)\) represents the cost of the car including tax.

The number of grams of a chemical in a pond is a function of the number of days, \(d\), since the chemical was first introduced. The function, \(f\), is defined by  \(f(d) = 550 \boldcdot \left(\frac{1}{2}\right)^d\).

1. What is the average rate of change between day 0 and day 7?
2. Is the average rate of change a good measure for how the amount of the chemical in the pond has changed over the week? Explain your reasoning.

A piece of paper, 0.004 inches thick, is being folded in half repeatedly.

1. Explain why the thickness in inches, \(t\), is a function of the number of times the paper is folded, \(n\).
2. Using function notation, represent the relationship between \(t\) and \(n\). That is, find a function, \(f\), so that \(t = f(n)\).

Function \(f\) represents the amount of a medicine, in mg, in a person's body \(t\) hours after taking the medicine. Here is a graph of \(f\).

1. How many mg of the medicine did the person take?
2. Write an equation that defines \(f\).
3. After 7 hours, how many mg of medicine remain in the person's body?

Graph of a decreasing exponential function, origin O. Horizontal axis, hours after taking medicine. Vertical axis, mg of medicine in the body. The function starts at the vertical axis at (0 comma 80) and goes through (2 comma 20) and (4 comma 5) and ends near y equal zero.  

Match each inequality to the graph of its solution.

Inequality graphed on a coordinate plane, origin O. Each axis from negative 10 to 8, by 2’s.  Line starts below x axis and to the left of y axis, slants upward and to right, passes through the points negative 6 comma negative 10, 0 comma negative 6, and 6 comma negative 2. The region above the line is shaded.