The graph shows the possible combinations of the number of sketchbooks, , and the number of markers, , that could be purchased for $24 at a certain store.
If Dana purchased sketchbooks and spent a total of $24 on sketchbooks and markers, how many markers did Dana purchase?
Each point on a graph of purchase combinations is an ordered pair: the horizontal count comes first, and the vertical count comes second. Find the given count on its axis, go to the line, then read the other axis. Keep the axes in order. Copying the given count as the answer confuses the two types of items.
Hints
- Hint 1
The horizontal axis counts sketchbooks. Start at on that axis and follow it straight up. Where does it meet the line?
- Hint 2
A point on the line is a purchase combination that costs $24. From the point above , move left to read the vertical coordinate, which counts markers.
Step-by-step
Read the matching point on the graph
Step 1Find Dana's point on the line
No Desmos needed. The given graph shows the combinations directly. Start at on the sketchbooks axis and move straight up to the line. That finds the point for Dana's sketchbooks and $24 total.
- Step 2
Read the marker count
From that point, move left to the markers axis. The vertical coordinate is , so Dana purchased markers. The is her sketchbook count, not her marker count. Choice B.