to find unit rate, it's typically done with the equation (y/X). in this case X=minutes and y=laps. so plug the numbers into the equation.(81/27). whatever the answers is, that's your constant of proportionality, or unit rate. multiply your unit rate with the minutes and divide the laps by the unit rate to find the minutes.
minutes=m
laps=l
unit rate=k
m×k=l
l/k=m
