I want to create a graph with time on the X-axis and distance on the Y-axis..

I want to have two Y-axes: miles on my primary vertical axis and kilometers on my secondary vertical axis. The primary axis will range from 10-90 miles. The corresponding number of kilometers would be 16.0934-144.841. The graph will show tick marks at 16.0934, 21.0934, 26.0934, etc. However, I would rather have tick marks at 20, 25, 30, etc. How can I do that?

I tried changing the "Format axis" - "Horizontal axis crosses" menu option, but it did not help.

Jeffrey