[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.
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 …
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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