Question

A can do pice of work in 6 hours, while B can do it in 8 hours. with the help of c they completed the work in 2.5 hours how much time can c complete the work done ​

Answer 1

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 2

Answer:

120/13

Step-by-step explanation:

A = 6hr

A in 1 hr = 1/6

B = 8 hr

B in 1 hr = 1/8

A+B+C = 2.5 Hr

A+B+C in 1 hr = 1/2.5

1/6 +1/8 + C = 1/ 2.5

=> C =120/13 ( * 1 hr work)

C =13/ 120 hr