Answer :
Answer: It will take 30 minutes to mow the lawn if Sam and Rocky work together.
Step-by-step explanation:
Given : Time taken by Sam to mow the lawn = 40 minutes
Time taken by Rocky to mow tha lawn = 120 minutes.
If they work together , then the time taken by them is given by :-
[tex]\dfrac{1}{t}=\dfrac{1}{40}+\dfrac{1}{120}\\\\\Rightarrow\ \dfrac{1}{t}=\dfrac{3+1}{120}\\\\\Rightarrow\ \dfrac{1}{t}=\dfrac{4}{120}=\dfrac{1}{30}\\\\\Rightarrow\ t=30[/tex]
Hence, it will take 30 minutes to mow the lawn if Sam and Rocky work together.