# You can make a difference

I remember back to early 2005 (before going for my post graduation), when I’d just started preparing for some competitive examination, that even though I had great ambitions, my knowledge, expertise, and confidence as a student was sorely lacking. My love for internet (as a source of information) made me stumble through various places on the web to know maths short cuts and quick maths tricks, but without much to gain from it.

Now, after having being there and facing it all as a student first and then as a facilitator (though I take good number of Quants classes for CAT aspirants, I would not liked to be called a tutor or a teacher. These titles should be reserved for people of great wisdom and learning) for over 4-5 years I felt I had a really good grip on things;  and even then, there were many things I am still struggling with

## Let The Process Begin

I’m starting the process by posting below an interesting formula of the topic- time and work . The aim is to initiate the process of collaborative learning. So anyone who wants to make a difference can post a comment with any explanation, formula, shortcut, trick, solved examples, etc. on the same topic (Time and Work for this post). If you’ve any question related to any topic in maths you can post it on the question-answer platform on this site.

You can also help by sharing the information of this platform with your friends or anyone who wants to help others and learn from others in the process.

## Time and Work Formula

I think the single most useful formula for the topic Time and Work is

N1H1D1E1W2 = N2H2D2E2W1

Where:

N1 and N2 = number of person

H1 and H2 = Hours worked by per person per day (assumed constant)

D1 and D2 = days

E1 and E2 = Efficiency

W1 and W2= Amount of work done

Consider this example to understand the applicability of this formula –

A piece of work can be done by 16 men in 8 days working 12 hours a day.How many men are needed to complete another work, which is three times the first one,in 24 days working 8 hours a day. The efficiency of the second group is half that of the first group?

Solution –

N1H1D1E1W2 = N2H2D2E2W1

16*12*8*1*3 = N2*8*24*0.5*1

N2 = (16*12*8*1*3)/ (8*24*0.5*1) = 48

So number of men required is 48.

Note – you can remove anything from formula is not given in the question. For example if the question would have been –

“A piece of work can be done by 16 men in 8 days working 12 hours a day.How many men are needed to complete another work, which is three times the first one,in 24 days working 8 hours a day.”

The applicable formula would have been –

N1H1D1W2 = N2H2D2W1

Since nothing is mentioned about efficiency, we remove it from both sides.

#### Vineet Patawari

Hi, I'm Vineet Patawari. I fell in love with numbers after being scared of them for quite some time. Now, I'm here to make you feel comfortable with numbers and help you get rid of Math Phobia!

## 130 thoughts to “You can make a difference”

1. nayan says:

how to solve multiplication of large numbers by vedic maths

2. Akshay says:

Hi sir

I am worst at math but want to prepare for bank exams atleast those where aptitude level is lower . I tried several times yet before but all waste .lost all hopes for aptitude .plz if possible get me some advice.

3. abc says:

formula is wrong
it is N*D*H*E/W=constant

4. Rajender Singh says:

Sir
Plz explain. me why we put value of pi 22/7

5. SINKUKUMAR says:

GOOD

6. SINKUKUMAR says:

THAT’S GOOD

7. Thanks for the auspicious writeup. It if truth be told
used to be a enjoyment account it. Look complicated to far added agreeable
from you! However, how could we keep in touch?

8. rishav Kaushik says:

1 day

9. hiteshwar says:

if the a+b do work in 10 days. b+c do work in 15 days. a+c do work in 12 days. then b independently do the work in how many days. solve it

1. Manoj Singh Tomer says:

24 days