Answer: Holly would take 60 minutes to clean alone.
Step-by-step explanation:
Let t = Time taken by Holly to clean alone.
Given: Time taken by Mia to clean alone = 30 minutes
Time taken by Mia and holly to clean their room = 20 minutes
Then,
[tex]\dfrac1t+\dfrac{1}{30}=\dfrac{1}{20}\\\\\Rightarrow\ \dfrac{1}{t}=\dfrac{1}{20}-\dfrac{1}{30}\\\\\Rightarrow\ \dfrac{1}{t}=\dfrac{3-2}{60}\\\\\Rightarrow\ \dfrac{1}{t}=\dfrac{1}{60}\\\\\Rightarrow\ t= 60[/tex]
Hence, Holly would take 60 minutes to clean alone.
