NC.8.SP.3 Interpreting Context for Line of Best Fit

• Jasmine will sell 50 ice-cream cones when the temperature is 0°F.

• For every 2° increase, Jasmine will sell 1 additional ice-cream cone.

• For every 1° increase, Jasmine will sell 2 additional ice-cream cones.

• When the temperature is 50°F, Jasmine will sell fewer ice-cream cones than usual.

Noah has a lunch account at the cafeteria. Noah can estimate the amount of money left in his lunch account using the equation y = 48 – 5x, where x represents the number of days he eats lunch. What is the meaning of the slope in the equation?

• He has $48 in his lunch account.

• He spends $5 per day eating lunch at the cafeteria.

• He has $43 in his lunch account after eating one day.

• He spends $10 of his lunch account after eating two days.

The equation C = 5.5b + 88 represents the relationship between carbohydrates (b) and calories (C) of some foods. What is the meaning of the slope?

• The number of calories increases by 5.5 each time a carbohydrate is added.

• The number of calories increases by 88 each time a carbohydrate is added.

• The total number of calories is 93.5.

• Most foods start with 88 calories.

Layla recorded her baby sister’s height, y, in inches, each month, x. The scatterplot shows her results.

Layla modeled the data approximately with the linear function y = 0.75x + 15. What does the slope of the line represent?

• Her sister grew about 15 inches each month.

• Her sister grew about 1 inch every 15 months.

• Her sister grew about 0.75 inch each month.

• Her sister grew about 1 inch every 0.75 month.

Madison collected data on airline flights. The equation for her set of data is M = 1,754 – 550h, where M represents the distance a plane is from its destination and h represents the time in hours. What is the meaning of the y-intercept?

• the distance the plane traveled per hour

• the distance the plane has traveled after 1 hour

• the length of time the plane takes to reach its destination

• the distance from the destination before the plane departs

An employee at an arcade determined he could use the equation y = 50 – 2x to predict the number of tokens a guest has, y, based on the number of minutes, x, the guest has been at the arcade. What is the meaning of the slope of the equation?

• Guests typically have 50 tokens when they first arrive.

• Guests typically have 50 tokens left when they leave.

• Guests typically earn 2 tokens per minute.

• Guests typically use 2 tokens per minute.

A school’s math department has money to spend on calculators. It uses the equation y = 1,000 – 80x to determine how much money is left in the account to spend on calculators, where x represents the number of calculators purchased. What is the meaning of the slope of the equation?

• Each calculator costs $80.

• Each calculator costs $1,000.

• The account had $80 before buying calculators.

• The account had $1,000 before buying calculators.

A cell phone company charges its customers a flat fee of $60 each month for calls and texts, plus an additional $5.00 for each gigabyte of data used. What does the y-intercept of the function represent?

• the flat fee for calls and texts

• the cost for each gigabyte of data used

• the total amount of a monthly bill with 1 gigabyte of data used

• the total amount of a monthly bill with 2 gigabytes of data used

The cost, y, in dollars, to purchase x school T-shirts includes a one-time setup fee, plus a charge per T-shirt. The cost is modeled with the linear function y = 6.67x + 35. What is the cost to purchase each T-shirt after the beginning setup cost is paid?

• $ 41.67

• $ 35.00

• $ 28.33

• $ 6.67

A water company uses the function T = 35 + 0.003w to calculate each customer’s monthly water bill, T, where w is the number of gallons of water used. Which statement describes the slope of the function?

• Customers are charged $35.00 each month.

• Customers are charged 0.003 of a cent each month.

• Customers are charged $0.003 per gallon of water used.

• Customers are charged $35.003 per gallon of water used.