WORK AND TIME RELEATED PROBLEMS

There is only one formula that you need to know to solve work related problems ->

WORK = RATE * TIME

 

Understand the information given in package properly and arrange it in tabular form as shown below. This will help you to understand the question and make all the information accessible to you easily.

Rate Time Work
X

 

For e.g. If X creates 50 pencils in 2 hours. The table could be created as below –

Rate Time Work
X 2 50

Rate = Work / Time = 50/ 2 = 25

Rate Time Work
X 25 2 50

 

Will try to solve some question to understand how should we proceed with work related questions.

Question 1 –

X creates 50 pencils in 2 hours, Y creates 20 pencils in 1 hours. How much time will both X and Y take to create 900 pencils together?

 

Let’s arrange the information in tabular format –

Rate Time Work
X 2 50
Y 1 20
X+Y 900

Now, calculate the Rate for X and Y using,

Rate = Work / Time

Rate Time Work
X 25 2 50
Y 20 1 20
X+Y 900

Rate of X = 25

Rate of Y = 20

Hence, Rate of X + Y = 45

Rate Time Work
X 25 2 50
Y 20 1 20
X+Y 45 900

Now calculate the required time X and Y will take to make 900 pencils,

Time = Work / Rate

= 900 / 45 = 20

 

 

Question 2 –

Working, independently X takes 12 hours to finish a certain work. He finishes 2/3 of the work. The rest of the work is finished by Y whose rate is 1/10 th of X. In how much time does Y finish his work?

 

Let’s arrange the given information in tabular form,

RATE TIME WORK
X x 12 1
X 2/3
Y x/10 1/3

Now, calculate the field,

x = 1/12

x/10 = (1/12 )/10 = 1/120

RATE TIME WORK
X 1/12 12 1
X 1/12 T1 2/3
Y 1/120 T2 1/3

We need to find T2,

T2 = work/ rate = (1/3) / (1/120)

= 120 / 3   = 40 hours

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