Problem:
A birdbath is designed to overflow so that it will be self-cleaning. Water flows in at the rate of milliliters per minute and drains at the rate of milliliters per minute. One of these graphs shows the volume of water in the birdbath during the filling time and continuing into the overflow time. Which one is it?
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Answer Choices:
A.
B.
C.
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E.
Solution:
Initially, volume increases with time as shown by graphs , and . But once the birdbath is full, the volume remains constant as the birdbath overflows. Only graph shows both features.
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions