Concepts of Ratio to Solve Double DI Questions

In this article we learn how we can calculate percentages easily by solving most repeatedly asked pattern in our examinations

 

Trick:1

Let us use ratio concept
14000:6000 =14:6=7:3=which is 2000 times
and difference gives Total male employees=8000

Trick: 2 

Conversion from degree to percentage in an easy way:
10% of 360 = 36 degrees (for calculating 10% put a point from right to left leaving one digit)
1% of 360 =3.6 degrees (for calculating 1% put a point leaving two digits from right to left)
5% of 360 =18 degrees (5% is half of 10%, it becomes 36/2=18 degrees)

1.  What is the total number of male employees in Company B?
Required one step calculation 

TRICK: To find male employees= (15%of 7-12%of 3) = .69*2000=1380(since from ratio trick)

Explanation:

360 degrees ==100%
54 degrees ==?
From above we can find 54 degrees = 15% (Total employees)
360 degrees=100%
43.2 degrees =? (12%) ( female employees)
43.2=36+3.6+3.6(12%)

2.  The total number of female employees of Company C is approximately what per cent of the total number of employees of Company B?

Required one step calculation 

8% of 3/15% of 7=23% (approx) (since from ratio trick)

3.  What is the difference between the total number of male employees and the total number of female employees in Company A? 

Required one step calculation 

(25% of 7-27% of 3) - 27% of 3) = .13=.13*2000=260 (since from ratio trick)

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