Each of the three people individually can complete a certain job in 3, 5, and 6 hours, respectively. What is the lowest fraction of the job that can be done in 1 hour by 2 of the people working together at their respective rates?
Choose the most appropriate option
A) 4/15  B) 7/30  C) 11/30  D) 7/18  E) 5/18
The two slowest people work at rates of 1/5 and 1/6 of the job per hour.   The sum of these rates is 1/5 + 1/6 = 11/30 of the job per hour.   The answer is 11/30.
<result>C</result>
Each of the three people individually can complete a certain job in 3, 5, and 6 hours, respectively. What is the lowest fraction of the job that can be done in 1 hour by 2 of the people working together at their respective rates?