A company has two types of machines, type R and type S. Operating at a constant rate, a machine of type R does a certain job in 36 hrs and a machine of type S does the same job in 18 hours. If the company used the same number of each type of machine to do the job in 2 hours, how many machines of type R were used?A. 3B. 4C. 6D. 9E. 12

Answer: C.  6Step-by-step explanation:Given : Time taken by Machine R to do the job = 36 hours Time taken by Machine S to do the job = 18 hoursLet x be the number of each type of machine to do the job.Then , according to the question the required equation will be :-[tex]\dfrac{x}{36}+\dfrac{x}{18}=\dfrac{1}{2}\\\\\Rightarrow\ x(\dfrac{1}{36}+\dfrac{1}{18})=\dfrac{1}{2}\\\\\Rightarrow\ \dfrac{x}{12}=\dfrac{1}{2}\\\\\Rightarrow\ x=\dfrac{12}{2}=6[/tex]Hence, the number of machines of type R were used =6