Let L be the number of laps Rita swam.
We know that John swam three times as many laps as rita, then John swam:
We also know that Rodell swam 25 more laps than John, then he swam:
We know that in total they swam 2125 laps, then we have the equation:
If we solve this equation we can know how many laps each of them swam:
Once we know the value of L we conclude that each of them swam:
Rita swam 300 laps.
John swam 900 laps.
Rodell swam 925 laps.
Finally, we know that for each lap they earned $2, then each of them earned:
Rita $600
John $1800
Rodell $1850