Dear Aspirants, Time and Work is a very easy topic but very important on which two to three questions are asked in almost every competitive exams either it be Bank Clerk, Bank PO, IBPS, SSC, RRB or any other state or central government exams.

Time and Work mainly deal with the time taken by a person to complete a given work.

Here we will deal with some most important cases and formulas used in time and work.

**Case 1 :**If a person can complete a work in N days then the work done by that person in 1 day is 1 / N

**Case 2 :**If a person A is N times more efficient than another person B, than A will take 1 / N time of the total time taken by B to complete the same work.

**Case 3 :**If a person A does a work in N days and the another person B can do it in M days then time taken by both A and B to complete that work is given by ( N M / N + M ) days

**Case 4 :**If A and B can complete a work in X days and A alone can finish that work in Y days, then number of days taken by B to complete the work is given by ( X Y / Y - X ) days

**Case 5 :**If P1 persons can do W1 work in D1 days working H1 hours whereas P2 persons can do W2 work in D2 days working H2 hours, then the relation between them is given by [ ( P1 D1 H1 ) / W1 ] = [ ( P2 D2 H2 ) / W2 ]

**Case 6 :**If A, B and C can do a work in X, Y and Z days respectively then they together can finish the work in [ X Y Z / ( X Y + Y Z + Z X ) ] days

**Case 7 :**If A and B can do a piece of work in X days, B and C can do the same work in Y days and A and C can do it in Z days then working together they can complete that work in [ 2 X Y Z / ( X Y + Y Z + Z X ) ]

**Case 8 :**If A takes X days more to complete a work than the time taken by ( A + B ) to do some work and B takes Y days more than the time taken by ( A + B ) to do same work. Then ( A + B ) do the work in √ab days.

**Case 9 :**If A, B and C can do a piece of work in X, Y and Z days respectively. The contract for the work is Rs R and all of them work together. Then

Share of A = [ R Y Z / ( X Y + Y Z + Z X ) ]

Share of B = [ R Z X / ( X Y + Y Z + Z X ) ]

Share of C = [ R X Y / ( X Y + Y Z + Z X ) ]

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