Time and Work questions tips and tricks

Important Facts:

1.If A can do a piece of work in n days, then A's 1 day work=1/n

2.If A's 1 day's work=1/n, then A can finish the work in n days.

Ex: If A can do a piece of work in 4 days,then A's 1 day's work=1/4. If A's 1 day’s work=1/5, then A can finish the work in 5 days

3.If A is thrice as good workman as B,then: Ratio of work done by A and B =3:1. Ratio of time taken by A and B to finish a work=1:3

4.If ‘M1’ persons can do ‘W1’ work in ‘D1’ days and ‘M2’ persons can do W2 work in D2, days then we have a very general formula in the relationship of M1 D1 W2 = M2 D2 W1. The above relationship can be taken as a very basic and all-in-one formula. We also derive 

A) More men less days and conversely more days less men. 

B) More men more work and conversely more work more men. 

C) More days more work and conversely more work more days. 

5..If we include the working hours (say T1 and T2) for the two groups then the relationship is 

M1 D1 T1 W2 = M2 D2 T2 Q1

Again, if the efficiency (Say E1 and E2) of the persons in two groups is different then the relationship is

M1 D1 T1 E1 W2 = M2 D2 T2 E2 W1

Now, we should go ahead starting with simpler to difficult and more difficult questions. 

Today we'll cover Time, Speed and Distance basic concepts. The type of questions varies from simple to quite complex. But No need to worry if you know the basics.

6.Definition of Variation: The change in two different variables follow some definite rule. It said that the two variables vary directly or inversely.

Its notation is X/Y=k, where k is called constant. This variation is called direct variation.

XY=k. This variation is called inverse variation.

7.Some Pairs of Variables:

i)Number of workers and their wages. If the number of workers increases, their total wages increase. If the number of days reduced, there will be less work. If the number of days is increased, there will be more work. Therefore, here we have direct proportion or direct variation.

ii)Number workers and days required to do a certain work is an example of inverse variation. If more men are employed, they will require fewer days and if there are less number of workers, more days are required.

iii)There is an inverse proportion between the daily hours of a work and the days required. If the number of hours is increased, less number of days are required and if the number of hours is reduced, more days are required.

8.Some Important Tips:

More Men -Less Days and Conversely More Day-Less Men.

More Men -More Work and Conversely More Work-More Men.

More Days-More Work and Conversely More Work-More Days.

Number of days required to complete the given work=Total work/One day’s work.

Since the total work is assumed to be one(unit), the number of days required to complete the given work would be the reciprocal of one day’s work. Sometimes, the problems on time and work can be solved using the proportional rule ((man*days*hours)/work) in another situation.