FOLLOW US:

Work from Days:
If A can do a piece of work in n days, then A's 1 day's work = 1/n

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Days from Work:
If A's 1 day's work = 1/n , then A can finish the work in n days.

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Ratio:
If A is twice as good a workman as B, then:

Ratio of work done by A and B = 2 : 1.

Ratio of times taken by A and B to finish a work = 1 : 2.

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I think the single most useful formula for the topic Time and Work is

N₂H₂D₂E₂W₁ = N₁H₁D₁E₁W₂

Where:

N₁ and N₂ = number of person

H₁ and H₂ = Hours worked by per person per day (assumed constant)

D₁ and D₂ = days

E₁ and E₂= Efficiency

W₁ and W₂= Amount of work done

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(a).   If a man can do a piece of work in 12 days he will do 1/12 of the work in 1 day . Conversely, if a man can do 1/12 of the work in 1 day he will do the work in 12 days .

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(b) .   Let the number of men engaged to do a piece of work be changed in the ratio 4:3 , the time required for the work will be changed in the ratio 3:4.

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(c).   A can do a piece of work in x days and B can do it in y days, if A and B working together will do the same work in

xy /x + y

days.

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(d).   A and B together can do a piece of work in x days and A alone can do it in y days, then B alone can do the work in

xy /y - x

days.

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(e).   Three person A,B and C can do a work in x,y and z days respectively then all of them working together can finish the work in

xyz /xy + yz + xz

days.

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