Given:
a.) Terri swam 3 laps in 2.5 minutes.
To be able to determine how long would it take her to swim 20 laps, we will be using ratio and proportions.

Where,
x = time to swim 20 laps
We get,






Therefore, Terri will take 16.67 or 16 2/3 minutes to swim 20 laps/