Question

if A person can finosh a work in 4 hour , if a person B will join A then they can finish it in 2hours . if a person C and B will do that work in 3hours . than find the time C will take to complete the work alone.​

Answer 1

Solutions :-

Given :
A can do a work in 4 hours.
A's one hour work = 1/4

(A + B) can do the same work in 2 hours.
(A + B)'s one hour work = 1/2

(B + C) can do the same work in 3 hours.
(B + C)'s one hour work = 1/3


Find the B's one hour work :-

(A + B)'s one hour work - A's one hour work
= 1/2 - 1/4
= (2 - 1)/4
= 1/4


Find the C's one hour work :-

(B + C)'s one hour work - B's one hour work
= 1/3 - 1/4
= (4 - 3)/12
= 1/12


C's one hour work = 1/12


Hence,
C can complete the work alone in 12 hours.

Answer 2

ANSWER:

_______________________________

There are three person A, B and C.

Given:

So, if person A can finish a particular task in 4hrs.

And if person B accompaies A in that same particular work the work can be finished in 2hrs.

And also person B and C can perform that work in 3 hrs.

To find:

The time taken by the person C to complete that particular work alone.

Person A's 1hr work =1/4.

Person A's and person B's one hour work =1/2.

Person B's and Person C 's one hour work =1/3.

Now we will first find the work done by B in one hour span.

So, for this we will subtract the Person A's and person B's one hour hr work by person A's one hour work.

$= \frac{1}{2} - \frac{1}{4} \\ \\ = \frac{2 - 1}{4} .........taking \: the \: lcm \\ \\ = \frac{1}{4}$

Now,

to find person C 's one hour work.

So for this we will subtract person B's and person C 's one hour work by B's one hour work.

$= \frac{1}{3} - \frac{1}{4} \\ \\ = \frac{4 - 3}{12}.......(taking \: \: lcm) \\ \\ = \frac{1}{12}$

Therefore,

Person C 's one hour work =1/12.

Hence person C can perform the same work in 12hrs.