Time and Work Problems – Formulas, Tips and Solved Examples

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Time and Work Questions

Nowadays competitive exams became very tough for candidates who are preparing competitive exams like SSC CGL, SSC CHSL, SSC MTS, Group D, Police Jobs, Banking, etc, though all most of the candidates have aptitude solving skills but they don't know how to solve it in less time or you can say they don't know time management, here you will how to solve the time and work aptitude questions with less time by using some simple tricks.

Trick-1 

If $M_1$ men can finish $W_1$ work in $D_1$ days and $M_2$ men can finish $W_2$ work in $D_2$ days then, Relation is

${M_1D_1}/ W_1 = {M_2D_2}/ W_2$
${M_1D_1W_2} = {M_2D_2W_1}$

 

Trick-2 

If M1 men finish W1 work in D1 days, working T1 time each day and M2 men finish W2 work in D2 days, working T2 time each day, then

$ {M_1D_1T_1}/ W_1 = {M_2D_2T_2}/ W_2$

 

Trick-3

If A completes a piece of work in 'x' days, and B completes the same work in 'y' days, then,

Work done by A in 1 day = $1/x$, Work done by B in 1 day = $1/y$
Work done by A and B in 1 day = $1/x + 1/y = {x + y}/{xy}$
Total time is taken to complete the work by A and B both = $({xy}/{x + y})$

Time and Work Questions With Examples

Question-1)

A alone can do a piece of work in 6 days and B alone in 8 days. A and B undertook to do it for Rs.3200. With the help of C they completed the work in 3 days. How much is to be paid to C ?

a) Rs.375

b) Rs.400

c) Rs.800

d) Rs.600

Ans - b

Solutions:

A’s 1 day’s work = $1/6$

B’s 1 day’s work = $1/8$

(A + B + C)’s 1 day’s work = $1/3$

C’s 1day’s work

= $1/3 - 1/6 - 1/8 = {8 - 4 - 3}/24 = 1/24$

Ratio of their one day’s work respectively

= $1/6 : 1/8 : 1/24$ = 4 : 3 : 1

Sum of the ratios = 4 + 3 + 1 = 8

C’s share = Rs.$1/8$ × 3200 = Rs.400

 

Test instructions :

  • Total number of questions : 20
  • Each question carries 1 mark
  • Negative marks of Each Questions: 0.25
  • Skiping questions No marks will deduct.
  • Time allotted : 30 minutes