If Elena swims 30 laps in 15 minutes, her rate is 2 laps per minute (30 laps ÷ 15 minutes = 2 laps/minute).
To find out how many laps she can swim in 10 minutes, we can multiply her rate by the number of minutes:
2 laps/minute x 10 minutes = 20 laps
Therefore, Elena can swim 20 laps in 10 minutes at the same rate.