1 and 2 1 upon 6 of a piece of work in 2 hours and B can do one upon 4 of the same work in 5 hours .in how many hours can both do it together?
Answers
Answer:
A does 1/6 of the work in 1 hour.
B does 1/8 of the work in 1 hour.
Let C take c hours to finish the work alone.
C does 1/c of the work in 1 hour.
In 1 hour all the three can do together
1/6 + 1/8 + 1/ c of the work.
Given A, B and C together finish in 2 1/2 hours.
In 1 hour they can do 1/2 1/2 = 2/5 of the work.
Hence 1/6 + 1/8 + 1/c = 2/5
=> 1/c = 2/5 -1/6 - 1/8
=> 1/c = (48–20–15)/120
=> 1/c = 13/120
=> c = 120/13 = 9 3/13 hours.
Therefore, C alone takes 9 3/13 hours to finish the work alone.
Answer:
Answer:
A does 1/6 of the work in 1 hour.
B does 1/8 of the work in 1 hour.
Let C take c hours to finish the work alone.
C does 1/c of the work in 1 hour.
In 1 hour all the three can do together
1/6 + 1/8 + 1/ c of the work.
Given A, B and C together finish in 2 1/2 hours.
In 1 hour they can do 1/2 1/2 = 2/5 of the work.
Hence 1/6 + 1/8 + 1/c = 2/5
=> 1/c = 2/5 -1/6 - 1/8
=> 1/c = (48–20–15)/120
=> 1/c = 13/120
=> c = 120/13 = 9 3/13 hours.
Therefore, C alone takes 9 3/13 hours to finish the work alone.