[CSAT][CAT] Basic Numeracy – Percentages – Concept (Tips & Tricks) – 2

Regaining back from our last post : [CSAT][CAT] Basic Numeracy – Percentages (Tips & Tricks) – 1, now lets learn the basic concept behind the percentage and what actually percent is.

Percent :

A percent is a ratio whose denominator is 100. So percent mean parts per 100.

Hence, the expression 20% simply means 20/100  = 0.20

I hope everyone must be knowing this very simple concept of percent, but even if you don’t lets see how it works mathematically :

How we can convert percent to a number ?

Step 1: To convert any percent to a number, just divide it by 100.

For e.g. : 3% = 3/100 = 0.03

50% =  50/100 = 0.50

600%  =  600/100 = 6

What if we want to convert a number to percent ??

Step 1: To convert any number to percent, multiply it by 100 and add a % symbol as suffix.

For e.g. : 6 = 6 x 100 = 600%

0.50  = 0.50 x 100 = 50%

0.03 = 0.03 x 100 = 3%

 

Isn’t it ??

so what will x% mean ?? – Reply in comments …

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Similarly fractions can be represented in percentage by reducing it to decimal and multiplying by 100

Fraction – > Decimal – > Decimal x 100 %

To do faster calculation in CSAT/CAT exam you should remember following fraction – percentage conversions. You will surely say it is not necessary to mug up these fraction – ratio conversion but it works that way only …. 😉 so just…

 

& learn these – Must for faster calculations and increasing your problem solving speed.

1/2 = 50%

1/3 =  33.33%

1/4 = 25%

1/5 = 20%

1/6 =  16.66%

1/8 = 12.5%

1/9 =  11.11%

1/12 = 8.33%

1/15 = 6.66%

1/16 = 6.25%

1/20 = 5%

……………………………………………………

2/3 = 66.66%

3/4 = 75%

5/6 = 83.33%

3/8 =  37.5%

5/8 = 62.5%

7/8 = 87.5%

So how the questions are asked in word format. ???????

Well its like this ..  Ramu is a milk vendor. Before going to a house he mix 30 litres of water to every 50 litres of milk. So what is percentage of milk in the solution ?

The ratio of milk to water is 5/3

so ratio of milk to solution is 5/(3+5) = 5/8

and 5/8 = 5/8 x 100 % = 62.50 %

Hence percentage of mil in the solution is 62.50 %.

Comments awaited below in comment section: 

Books to be referred for questions and concept : CSAT

 

Books to be referred questions and concept : CAT/MBA

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In the next article I will be coming up with the details of other subtopics and questions related to the sub topics. I will be keeping it at tortoise’s pace as I discussed in my article How CSAT – UPSC Prelims paper – 2 can help you in your sweet journey !!!  and you will find that by devoting less than an hour, how you could reach your target of 160+ score.

Friends, You can post problems or questions related to this topic at Forum – Prelims Paper -2 .  Lets discuss as much questions as possible in forum. 

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