Time and work Tricks for Competitive Exams Part – 9th

The conceptual Questions with their solutions continues.:-

Type 3^rd   :- Questions based various workers:-

In these type of questions you just have to read the questions carefully to analyse the given data in the question and establish a relation between various categories of work in any one category. Then calculate the required answer with the help of formula given in this post.

Type 1^st :- Questions with “or”

Q16. 3 men or 4 women can do a work in 43 days. How long will 7 men and 5 women take to do the same work together?

Sol. Analyse the question clearly. The word “or” in the above questions indicates that 3 men can do a work in 43 days while 4 women can also do the same work in 43 days, this will help us in getting a relation between men and women for further calculation. This relation is must for the solution of such questions.

3 men can do work → 43 days.

4 women can do the same work → 43 days.

We observe that the number of days are same in both conditions therefore we can say that

3 men = 4 women

Lets denote men by “M” and women by “W”.

3 M = 4 W

1 M = (4/3) W

Now to calculate no. of days for (7M and 5W)

Using the above relation we get that

7M + 5W = 7(4/3)W + 5W

= (28/3)W + 5W

= (43/3)W

Now our question become basic question As:-

4 women can do a work in 43 days then in how many days will (43/3) women take to do the same work?

Now again analyse the data As:-

M₁ = 4      D₁ = 43      M₂ = 43/3         D₂ = ?

Using formula M₁ × D₁ = M₂ × D₂  we get,

 4 × 43 = (43/3) × D₂

D₂ = 12 days

Hence the required answer is 12 days.

Q17. 1 man or 2 women or 3 boys can do a work in 44 days. In how many days 1 man, 1 woman and 1 boy can do the same work together?

Sol. Analyse the question clearly. The word “or” in the above questions indicates that 1 man can do a work in 44 days, 2 women can also do the same work in 44 days while 3 boys can do the same work in 44 days, this will help us in getting a relation between man, women and boys for further calculation. This relation is must for the solution of such questions.

1 man can do work → 44 days.

2 women can do the same work → 44 days.

3 boys can do the same work → 44 days.

We observe that the number of days are same in all conditions therefore we can say that

1 man = 2 women = 3 boys

Lets denote man by “M”, women by “W” and boys by “B” .

1 M = 2 W = 3 B

1 M = 2 W ................................... relation 1^st

3 B = 2 W

1 B = (2/3) W ............................... relation 2^nd

Now to calculate no. of days for (1M, 1W and 1B )

Using the above relations we get that

1M + 1W + 1B = 2W + 1W + (2/3)W

= (2/3)W + 3W

= (11/3)W

Now our question become basic question As:-

2 women can do a work in 44 days then in how many days will (11/3) women take to do the same work?

Now again analyse the data As:-

M₁ = 2      D₁ = 44      M₂ = 11/3         D₂ = ?

Using formula M₁ × D₁ = M₂ × D₂  we get,

 2 × 44 = (11/3) × D₂

D₂ = 24 days

Hence the required answer is 24 days.

(Note you may say that this is so long but dear this is the only way to explain the whole concept of the question to you now its upto you that how fast and short handedly you can solve these type of questions)   

                                                                    

The Various Questions related to this and other concept which are frequently asked in the examinations will be presented to your for self study on this blog soon, so keep visiting and sending your suggestions and requirements too to us through the forum.

More types of questions will be followed soon on this blog........................