I currently have a list box which displays the length of an item. I.e.
2.23
8.12
2.05
6.14
3.11

In a second list box next to it I want to display the start time of each item if they were to be run sequentially. I.e.
2.23 0.00
8.12 2.23
2.05 10.35
6.14 16.49
3.11 20.00

How would I achieve this?