Varies Directly or Not? Pre-Quiz

​

Equation 1: y =3x+2    Equation 2: y = (2/3)x+0

Sarah says that equation 2 varies directly (or is proportional).  

Sammie says that equation 1 varies directly (or is proportional). 

Who is correct and WHY?

​

• Sarah is correct because you can't vary directly with a fraction. 

• Sammie is correct because both the slope and the y-intercept are whole numbers.

• Sarah is correct because the y-intercept = 0

• Neither is correct

Tags

CCSS.8.F.A.2

CCSS.HSF.IF.C.9

Mary takes a summer job at a grocery store. To estimate her weekly pay, she makes a graph of the amount of money she will get paid for working different numbers of hours. According to her graph, what is her hourly pay rate? 

• $10 per hour

• $65 per hour

• $6.50 per hour

• $6 per hour

Tags

CCSS.HSF.LE.B.5

Which of the following situations can a linear model be written where y varies directly with x?

• Suppose you earn $10 every 3 minutes. Let x be the number of minutes and y be the money earned. 

• Suppose you start with $-12 and lose $8 every 2 minutes. Let x be the number of minutes and y be the money earned. 

• Suppose you start with $4 and lose $13 every 5 minutes. Let x be the number of minutes and y be the money earned. 

• Suppose you start with $9 and earn $4 every 5 minutes. Let x be the number of minutes and y be the money earned. 

Tags

CCSS.8.F.A.3

What is the rate of change for the cost of Daily Mix? 

• $1 per month

• $3 per month

• $4 per month

• $5 per month

Tags

CCSS.HSF-LE.A.1B

What is the y-intercept for the cost of Daily Mix? 

• 0

• 1

• 3

• 4

Tags

CCSS.HSF.LE.B.5

What is the rate of change for the cost of HiFi Beats? 

• $1 per month

• $3 per month

• $4 per month

• $5 per month

Tags

CCSS.HSF.IF.B.4

What is the y-intercept for the cost of HiFi Beats? 

• 0

• 1

• 3

• 4

Tags

CCSS.8.EE.B.5

In which of the following linear equations does x vary directly with y?

• ​ y = 3x+15

• ​ y = 3x+2

• ​ y = 12x+2

• ​ y = 23x+0

Which equation matches the following linear relationship? 

Suppose you start with $18 and EARN $7 every 5 minutes.

Tags

CCSS.8.F.B.4

CCSS.HSF.LE.A.2

The amount collected from the sales of caps is a function of the number of caps sold. 

If the costs of the 6 cap sales shown in the table are graphed with number of caps sold on the horizontal axis and the amount on the vertical axis, what does the slope of the graph represent?

• a rate of $10 per cap

• the total cost of all the caps

• the starting point

• the run over the rise

Tags

CCSS.HSF.LE.B.5