5.5.6 Practice

1. A new bicycle sells for $300. It is on sale for $\frac{1}{4}$ off the regular price. Select three expressions that represent the sale price of the bicycle in dollars.

1. $300\cdot <!--\; \cdot \; -->\frac{1}{4}$
2. $300\cdot <!--\; \cdot \; -->\frac{3}{4}$
3. $300\cdot <!--\; \cdot \; -->(1-<!--\; -\; -->\frac{1}{4})$
4. $300-<!--\; -\; -->\frac{1}{4}$
5. $300-<!--\; -\; -->\frac{1}{4}\cdot <!--\; \cdot \; -->300$

1. The value of the computer, in dollars, when it is purchased.
   

2. The value of the computer, in dollars, after 1 year.
   

3. The value of the computer, in dollars, after 2 years.
   

3. Which of the following expressions would represent the value of the computer, in dollars, after $t$ years?

4. Use your equation from question 3 to find $v$ when $t$ is 5. What does this value of $v$ mean?

5. A piece of paper is folded into thirds multiple times. The area, $A$, of the piece of paper in square inches, after $n$ folds, is $A=90\cdot <!--\; \cdot \; -->(\frac{1}{3}{)}^n$ .
   

1. What is the value of $A$ when $n=0$?

2. How many folds are needed before the area is less than 1 square inch?

The area of another piece of paper in square inches, after $n$ folds, is given by $A=100\cdot <!--\; \cdot \; -->(\frac{1}{2}{)}^n$.

6. What does the number 100 mean in this situation?

7. What does the number $\frac{1}{2}$ mean in this situation?

8. Lin has 13 mystery novels. Each month, she gets 2 more. Select three expressions that represent the total number of mystery novels Lin has after 3 months.

1. $13+2+2+2$
2. $13\cdot <!--\; \cdot \; -->2\cdot <!--\; \cdot \; -->2\cdot <!--\; \cdot \; -->2$
3. $13\cdot <!--\; \cdot \; -->8$
4. $13+6$
5. $19$

1. What are the coordinates of point $A$?

2. What are the coordinates of point $B$?

3. Which of the following equations would represent the chemical, $C$, after time, $x$, from the graph?

10. The graph shows the amount of a chemical in a water sample at different times after it was first measured. Select two statements that are true.

    

1. The amount of the chemical in the water sample is decreasing exponentially.
2. The amount of the chemical in the water sample is not decreasing exponentially.
3. It is not possible to tell for certain whether the amount of the chemical is decreasing exponentially.
4. When it was first measured, there were 2,000 mg of the chemical in the water sample.
5. After 4 hours, there were 200 mg of the chemical in the water.

11. The height of a plant in mm is 7. It doubles each week. Select two expressions that represent the height of the plant, in mm, after 4 weeks.

1. $7+4\cdot <!--\; \cdot \; -->2$
2. $7\cdot <!--\; \cdot \; -->2^4$
3. $2+7^4$
4. $7\cdot <!--\; \cdot \; -->2\cdot <!--\; \cdot \; -->2\cdot <!--\; \cdot \; -->2\cdot <!--\; \cdot \; -->2$
5. $7\cdot <!--\; \cdot \; -->2\cdot <!--\; \cdot \; -->4$