Identify the graph that best represents the relationship between the number of songs on eMusic.com Jared purchased at $1.29 a song and the total cost of his purchase.
A
B
C
D
A.
Correct! The cost will increase at a constant rate of $1.29 per song.
B.
Incorrect. Total cost would increase not decrease.
C.
Incorrect. If you buy more songs, the total cost will increase.
D.
Incorrect. Total cost would increase but not at different rates.
Which statement is true for the graph?
A. A pizza with 3 topping costs $15.
Incorrect. A pizza with 4 toppings cost $15.
B. For every two toppings added, the cost increases $3.
Correct! Three up ($3) for every two right (2 toppings).
C. Each topping on a large pizza costs $1.
Incorrect. Each topping is $1.50.
D. The minimum cost of a large pizza is $8.
Incorrect. The line starts at $9. Notice it’s between the 8 and 10.
Look at the graph below. Which is the best interpretation of this graph?
A. Cynthia runs at a constant rate of 5 miles every 30 minutes.
Incorrect. 30 minutes would correspond to 10 miles.
B. Jorge earns $15 for each hour worked.
Incorrect. Earnings depends on hours worked. Hours worked would be the x-axis and earnings would be the y-axis. Each hour worked would probably mean 60 min on the x-axis and the y-value would be $20. If you thought the x-axis was in hours, then his pay would not be a point on the graph.
C. For every 15 minutes of laser tag, Miles pays $5.
Correct! Payment would depend on minutes play laser tag. Notice every 15 minutes increase on the x-axis made a $5 increase on the y-axis.
D. At Sandwich Express, Miguel makes 15 sandwiches every half hour.
Incorrect. If you look at 30 minutes (half hour), then he would make 10 sandwiches.
Which situation best describes the graph shown below?
A. A boom box that costs $36 will decrease in value at 6% per year.
Incorrect. 6% of 36 is $2.16 not $6 per year.
B. A group of 36 students in the student council will sell Valentine candies for $6 each.
Incorrect. This would be 36 times $6.
C. A 36-gallon Hummer’s gas tank will burn 6 gallons per hour.
Correct! Burning gas means that the gas in the tank is decreasing 6 gallons each hour.
D. An online flower company charges 36 cents per flower, plus a shipping fee of $6.
Incorrect. The more flowers that you purchase the graph would increase. Also, the shipping fee is the one time fee usually representing the y-intercept.
A Boeing 737, at 4500 feet, descends into William P. Hobby Airport in Houston at a rate of 180 feet per minute, and a Learjet 45, at 900 feet, is climbing at a rate of 90 feet per minute. Which graph shows when the two planes will be at the same altitude?
A
B
C
D
A.
Incorrect The y-intercept (starting altitude) for 900 feet was above the line.
B.
Correct! Way to check your y-intercepts and slopes.
C.
Incorrect. Did you look at your y-intercepts (starting altitude)? One plane started at 4500 feet and the other started at 900. Notice in this graph that one line starts at 0.
D.
Incorrect. Did you look at your y-intercepts (starting altitude)? One plane started at 4500 feet and the other started at 900. Notice in this graph that one line starts at 0.
Luis is choosing between two International Calling Plans listed below to make business calls to Mexico. The graph shows the relationship between the total cost per month of each plan and the hours of usage.
Plan A
Monthly plan fee of only $75.00, plus per - minute rate.
Rate per minute ($/min): $0.25
Plan B
Monthly plan fee of only $15.00, plus per - minute rate.
Rate per minute ($/min): $0.50
According to the graph, which of these statements is true?
A. Plan A would cost less than Plan B if Luis called internationally less than 4 hours a month.
Incorrect. You were looking at the wrong side of the graph or the work colors. First, locate “less than 4 hours” on the x-axis and cover up the other side. Second, look for the line that falls below the other, representing “cost less.”
B. Plan A would cost less than Plan B if Luis called internationally more than 4 hours a month.
Correct! You located the right side of the graph to look at before you compared plans.
C. Plan B would cost less than Plan A if Luis called internationally more than 4 hours a month.
Incorrect. You were looking at the wrong side of the graph or the work colors. First, locate “more than 4 hours” on the x-axis and cover up the other side. Second, look for the line that falls below the other, representing “cost less.”
D. Plan B would cost less than Plan A if Luis called internationally for exactly 4 hours a month.
Incorrect. The cost (y-axis value) is the same at exact 4 hours.
Leda's heart rate peaked after sprinting 3 miles. Her heart rate fell at a constant rate for several minutes until it leveled off to its regular rate. Which of the following graphs best represents this information?
A
B
C
D
A.
Correct! Peaked means that it was at its highest and fell means decreased.
B.
Incorrect. This is a constant rate per minute. “Fell at a constant rate” means decreased the same amount per minute.
C.
Incorrect. It decreased first then it levels off.
D.
Incorrect. “Leda’s heart peaked” is the starting point. “Fell at a constant rate” means decreased the same amount per minute.
The function graphed shows a relationship between x and y. Which of the following relationships can best be represented by this graph?
A. The total number of pounds of sugar used, y, based on x, the total number batches of cookies made.
Incorrect. Remember to use the word increase or decrease when talking about the x and y values. For example, if number of minutes increase, what happens to the total cost?
B. The total cost of international calls per month, y, based on x, the number of minutes used.
Incorrect. Remember to use the word increase or decrease when talking about the x and y values. For example, if number of minutes increase, what happens to the total cost?
C. The total number of gallons of gas left in a gas tank, y, based on x, the total number of miles driven.
Correct! The total number of gallons of gas left decreases based on the total number of miles driven.
D. The total amount of hourly earnings, y, based on x, the total number of hours worked.
Incorrect. Remember to use the word increase or decrease when talking about the x and y values. For example, if number of minutes increase, what happens to the total cost?