Lesson 8: Practice Problems

Problem 1

Lin and Andre biked home from school at a steady pace. Lin biked 1.5 km and it took her 5 minutes. Andre biked 2 km and it took him 8 minutes.

Draw a graph with two lines that represent the bike rides of Lin and Andre.
For each line, highlight the point with coordinates $(1, k)$ and find $k$ .
Who was biking faster?

Problem 2

Match each equation to its graph.

Graph 1

A line is graphed in the coordinate plane with the origin labeled “O”. The numbers 0 through 5 are indicated on the horizontal axis. The numbers 0 through 5, are indicated on the vertical axis. The line begins at the origin. It moves steadily upwards and to the right passing through the points with coordinates 1 comma four fifths, and 5 comma 4.

Graph 2

Graph 3

Graph 4

Graph 5

Graph 6

$y = 2 x$
$y = \frac{4}{5} x$
$y = \frac{1}{4} x$
$y = \frac{2}{3} x$
$y = \frac{4}{3} x$
$y = \frac{3}{2} x$

Graph 1
Graph 2
Graph 3
Graph 4
Graph 5
Graph 6

Problem 3

The graphs below show some data from a coffee shop menu. One of the graphs shows cost (in dollars) vs. drink volume (in ounces), and one of the graphs shows calories vs. drink volume (in ounces).

vs volume

A coordinate plane with the origin labeled “O”. The horizontal axis is labeled “volume in ounces” and the numbers 0 through 26, in increments of 2, are indicated. The vertical axis has the numbers 0 through 6 indicated. The points with coordinates 10 comma 3 point 7 5, 12 comma 4, 16 comma 4 point 5, and 24 comma 4 point 9 5 are indicated.

vs volume

Which graph is which? Give them the correct titles.
Which quantities appear to be in a proportional relationship? Explain how you know.
For the proportional relationship, find the constant of proportionality. What does that number mean?