Problem:
Elisa swims laps in the pool. When she first started, she completed  laps in  minutes. Now she can finish  laps in  minutes. By how many minutes has she improved her lap time?
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Answer Choices:
A.  
B.  
C.  
D.  
E.  
Solution:
When Elisa started, she completed a lap in minutes. Now she can complete a lap in minutes. She has improved her lap time by or minute.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions