Answer: C. 6
Step-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 hours
Let x be the number of each type of machine to do the job.
Then , according to the question the required equation will be :-

Hence, the number of machines of type R were used =6
2/3 is the answer in lowest terms. i hope this helps!
Answer:
B. 1
Step-by-step explanation:

Plug in 20 to W making 20-8, so your answer would be 12 :)