Her swimming rate can either be written as 1.6 laps per (one) minute or as 0.625 minutes per lap = 37.5 seconds per (one) lap.
In terms of number of laps per minute, the answer is
20
laps
12.5
minutes
=
1.6
laps per minute.
In terms of the number of minutes per lap, the answer is
12.5
minutes
20
laps
=
5
8
=
0.625
minutes per lap. This is the same as
0.625
min
lap
⋅
60
sec
min
=
37.5
sec
lap
The faster she goes, the more laps she can do in a minute and the fewer minutes (or seconds) it takes her to do one lap.