Question

A and b can do a piece of work in 18 days b and c can do it in 24 days.If a is twice as good a work man as c find in what time b alone can do it

Answer 1

B alone can do it in 36 days.

Step-by-step explanation:

A and B can do a piece of work in 18 days

So, Work dond by A and B in one day = A + B = 1 / 18  

B and C can do it in 24 days

So Work done by B and C in one day = B + C = 1 / 24 --- Eq( 1 )

A is twice as good as a work man as C

⇒ A = 2C

Substituting A = 2C in A + B = 1 / 18

⇒ 2C + B  = 1 / 18 ---- Eq ( 2 )

Subtracting Eq( 1 ) from Eq)( 2 )

•  B + 2C = 1 / 18

•  B + C = 1 / 24

       -      -       -

_____________________

• C = 1 / 18 - 1 / 24

_____________________

⇒ C = ( 4 - 3 ) / 72

⇒ C = 1 / 72

Substituting C = 1 / 72 in B + C = 1 / 24

⇒ B + 1 / 72 = 1 / 18

⇒ B = 1 / 18 - 1 / 72

⇒ B = ( 3 - 1 ) / 72

⇒ B = 2 / 72

⇒ B = 1 / 36

Therefore B alone can do it in 36 days.

Answer 2

Step-by-step explanation:

Given A and b can do a piece of work in 18 days b and c can do it in 24 days.If a is twice as good a work man as c find in what time b alone can do it

• (a + b)’s work in 1 day be 1/18
• (b + c)’s work in 1 day be 1/24
• A’s work in 1 day is 2 times of C’s work
•                                             = 2 x C
• Now A’s work in 1 day will be C’s work in 2 days.
• Therefore (A + B)’s work in 1 day = B’s work in 1 day + C’s work in 2 days.
•     So 1/18 = 1/24 + C’s work in 1 day.
• So required value of C’s work in 1 day = 1/18 – 1/24
•          = 4 – 3 / 72
•                      = 1/72
• Now B’s work in 1 day will be 1/24 – 1/72
•    = 3 – 1 / 72
•              = 2/72
•             = 1/36
• Therefore B alone will do it in 36 days.  

Reference link will be

https://brainly.in/question/11044980