Yes, to those who had studied it was fairly obvious what the solution was, but the phrasing was such that to those who were just trying to wing it failed miserably.
I must stress this was a single question on a single first-year exam. Not representative of the whole course in the slightest.
You want bytes/seconds (i.e. quantity of data per unit time).
You have:
- Distance per unit time (km/h)
- Payloads per unit distance (# of flights per km)
- Quantity of data per payload (bytes per flight)