Scatter chart with two sets of data shown using only one set of points

No. Sorry, I don't understand what you are trying to achieve... Cnn you try again?

What column is supposed to be the the X data and which is supposed to be the y data? As you have it now, you are asking it to plot both C and D against column B (a text column). Are you wanting to plot column D (y) against column C (x)? If so, go into the existing chart, pull up the "select data" dialog, remove the existing series, then add a series where you tell it to use column D for the Y data and column C for the x data.

Ummmm. It's the same attachment.

We've all done it... many times.

Here's a first attempt for you:

Is series1 in the new attachment what you are looking for (average cost per mile vs. miles driven), or are you looking to create the picture where cost per trip is plotted against miles driven?

If the former, it looks like all you should need to do is delete series2. If the latter, you will need to add a column to the spreadsheet to enter or calculate total cost per trip (as miles*average cost per mile?).

Why the insistence on attaching workbooks for such simple questions?

If you want to make an XY Scatter chart, arranging the data first will save lots of time. Put the X values into one column, the Y values in the next column, put a series name in the cell immediately above the Y values, and leave the cell above the X values blank. The blank cell tells Excel what you're trying to do. Select the range and insert the chart.

XYDataAndChart1.png

If the data isn't so nicely arranged, make the chart with any convenient data. Right click on the chart, and choose Select Data from the pop up menu. Select the series from the list in the lower left quadrant of the dialog, and click the Edit button. You'll get this nice dialog that lets you select the ranges that contain series name, X values, and Y values.

XYDataAndChart2.png