Answer:
[tex]\frac{1}{4}\:\mathrm{of\:an\:hour\: or\:}15\:\mathrm{minutes}[/tex]
Step-by-step explanation:
If the faucet fills [tex]\frac{1}{3}[/tex] of the water cooler in [tex]\frac{1}{12}[/tex] of an hour, then it will take the faucet [tex]\frac{1}{\frac{1}{3}}\cdot \frac{1}{12}=3\cdot\frac{1}{12}=\fbox{$\frac{1}{4}$}[/tex] of an hour to fill the faucet completely.
