A clock time the sheet will actually do arithmetic with.
The tracker exports each van's arrival as text, so you cannot subtract one from another to get a duration. Convert each arrival to a real time value in column C.
Solve it on your own to keep the bonus. Each hint gets one step closer to the formula.
The same formula in the other shapes it takes at work.
This is the grid you start with. Cell references in the task — B6, C2 — point at the row numbers and column letters below.
| A | B | C | |
|---|---|---|---|
| 1 | Vehicle | Arrived (text) | Arrival time |
| 2 | Van 1 | 08:15 | |
| 3 | Van 2 | 10:30 | |
| 4 | Van 3 | 14:45 |
Text that looks like a time is not a time, and the difference only shows up when you try to use it: subtracting one text arrival from another gives an error rather than a duration. Converting on the way in is what turns an export into something you can measure with.