Working at their respective constant rates, Paul, Abdul and Adam alone can finish a certain work in 3, 4, and 5 hours respectively. If all three work together to finish the work, what fraction Q of the work will be done by Adam?
Answers.
A) 1/4	B) 12/47	C) 1/3	D) 5/12	E) 20/47
Let the total work be 60 units. Pual does   60/3= 
<gadget id="calculator">  60/3</gadget>
<output>20</output>
20 units of work per hr. abdul does 15 units per hr and adam does 12 units per hr. If all work together they do (20 + 15 + 12)= 
<gadget id="calculator">(20 + 15 + 12)</gadget>
<output>47</output>
47 units per hr. So the time taken to finish the work= 60/47 hrs.   adam will do 60/47 * 12 units of work in 60/47 hr . fraction of work adam does =work done by adam / total work   Q&gt;( 60/47 *12)/60 =12/47   Answer 12/47
<result>B</result>
Working at their respective constant rates, Paul, Abdul and Adam alone can finish a certain work in 3, 4, and 5 hours respectively. If all three work together to finish the work, what fraction Q of the work will be done by Adam?