Working together, four pugs can clean their house in 45 minutes. In how many minutes will 15 pugs working together be able to clean their house? Let's think first. Chain of thought:
If four pugs can clean their house in 45 minutes, one pug will take 4 * 45 = 180 minutes. Since one pug working alone takes 180 minutes to clean the house, fifteen pugs working together will be able to clean their house in 180 / 15 = 12 minutes.
Therefore, the answer is 12.