I am calculating times by dividing a distance by a speed. The results are in
cells formatted hh:mm but always seem to be rounded down so that the sum of
the column may be several minutes out, compared to the times displayed.

If I reformat the cells hh:mm:ss then I can see for example what was 01:32
displayed as 01:32:57. I want this to appear as 01:33.

Any ideas?