Question 1128413
A park has two sprinklers that are used to fill a fountain. One sprinkler can fill the fountain in 4 h, whereas the second sprinkler can fill the fountain in 12 h. How long will it take to fill the fountain with both sprinklers operating? 
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The "4 hour" sprinkler is equivalent to 3 12 hour sprinklers.
= 4 of the 12 hour sprinklers
---> 3 hours to fill the fountain.