Aptitude: Time and Work

In this post we are going to learn about the Time and work problems asked in the competitive exams. Nowadays it is very difficult to find a question paper without this topic. In TNPSC exams, 2-4 questions can be expected from this topic alone in the TNPSC aptitude section.

Just consider this simple example, before going for the problem types.

Let us assume that you have 3 friends A, B and C. You want to make a soft copy of your handwritten notes. There are totally 60 pages. Your friend A can type 4 Pages in one hour, friend B can type 5 Pages in one hour and Friend C can type 6 pages in one hour. (There are three computer all connected together, hence sharing is possible)

If they work/type individually

If A alone types, he will finish it in 60/4 = 15 hours
If B alone types, he will finish it in 60/5 = 12 hours
If C alone types, he will finish it in 60/6 = 10 hours

 If any two of them work together

If A(4) and B(5) type together (4+5 = 9 pages in one hour), they will finish it in 60/9 = 6 4/9 hours

If B and C work together, they will finish it in 60/11 = 5 5/11 hours

If A and C work together, they will finish it in 60/10 = 6 hours 

 If all of them work together

If A, B and C work together, they will finish it in 60/15 = 4 hours.

In the above example the total work is given in the question itself so we can use it directly.

Now, let us see the different types of Time and Work problems usually asked in competitive exams.

Type 1: Finding total days from two workers

Question 1 :  If A can do a work in 24 days and B can do a work in 8 days, how many days will they take to complete a work if they work together.

Step 1 : Find the amount of work done in one day individually

Work Done in one day by A = 1/24

Work Done in one day by B = 1/8

Step 2: Find the combined amount of work done by both A and B

          

     

  

 

Step 3: Take inverse ie 6/1 = 6 Days.

Remaining types will be added soon...