DI – How to Approach Pie Chart Problems in Data Interpretation


Analysis of Data Interpretation questions asked in previous exams

Exam No of Questions
In Clerk In PO
Prelims Mains Prelims Mains
IBPS RRB 15 5 10 20
SBI 10 20 10 20
BOB 5 10 15 10
RBI 15 20 10 15
No of Questions
SSC CGL 3 – 5
SSC CHSL 5

 

Kind of Data are represented as PIE CHARTS usually:

Pie charts are useful for displaying data that are classified into nominal or ordinal categories.

  1. Nominal data are categorized according to Descriptive or qualitative information such as county of birth or type of pet owned. Ordinal data are similar but the different categories can also be ranked, for example in a survey people may be asked to say whether they classed something as very poor, poor, fair, good, very good.
  2. Pie charts are generally used to show percentage or proportional data and usually the percentage represented by each category is provided next to the corresponding slice of pie.
  3. Pie charts are good for displaying data for around 6 categories or fewer. When there are more categories it is difficult for the eye to distinguish between the relative sizes of the different sectors and so the chart becomes difficult to interpret.

How to approach and get data from Pie charts?

Degree approach

The central angle  in circle represents 360° so any part or segment in a pie chart is calculated as a proportion of 360° .

Percentage Approach

In this case, any part or segment in a pie chart is calculates as a part of 100%.

Percentages Degree
Total 100% 360°
Hence 1% 3.6°
Kerala 10% 36°
Andhra Pradesh 20% 72°
Srilanka 25% 90°
Maharashtra 15% 54°
Tamil Nadu 30% 108°

 

  • Always keep in your Mind that in the circular Graph or Charts 100% =360 Degree .
  • Formulas and Full Concept of Percentage ,Average, Approx. Value and Ratio.
  • While solving keeps in mind that which Type of chart is using in the question this will help you to get the correct answer.
  • First Read the Question and try to interrupt in the question as the Topics says DATA INTERPRETATION.Because every bank wants the PO who can handle and Play with numbers of Figures just in few seconds and not just calculate it with closed eyes.
  • The whole of the DA concept is based on Calculation so if you want to be perfect in DA and DI don’t even use calculator at home while practicing.One who can calculate fast and accurate even Large numbers without calculator is 50% ready for the Any Aptitude test.
  • Try to use your mind while solving DA questions. Try to write only important Lines on the paper and Others just write and calculate in your Mind.This can be easily done by practicing More and More at Home.
  • Don’t feel confusing and no need to Try and Solve all the questions only Focus on questions with you are more familiar and you find yourself in such a way that you can solve the question accurately.
  • Try to solve all types of Questions while practicing this will not confuse you in the exam.

Beginners Level:

The Following piechart shows the amount of subscripttion generated for India Bonds from different category for investors.

  1. If the total investment flows from FII’s were to be doubled in the next year and the investment flows from all other sources had remained constant at their existing levels for this year, then what would be the proportion of FII investment in the total investment into India Bonds next year (in US $ millions) ?

Solution

FII’s currently account for 33 out of 100.

If their value is doubled and all other investments are kept constant then their new value would be 66 out of 133 = approximately equal to 50%

2. If the total investment other than by FII and corporate houses is Rs 335,000 then the investment by NRI’s and Offshore funds will be (approximately) ?

Solution

Investment other than NRI and corporate houses is 33% = 335000.

Also, investment by offshore funds and NRI’s is equal to 27%.

Hence, 27 x 335,000/33 = 274 090.909

3. What percentage of the total investment is coming from FII’s and NRI’s ?

Solution

(33 + 11) = 44

4. If the investment by NRI’s are Rs 4,000 then the investments by corporate houses and FII’s together is:

Solution

(67/11) x 4000 = 24 363.6364

In the corporate sector, approximately how many degrees should be there in the central angle ?

Solution

34 x 3.6 = 122.4 (since 1% = 3.6 degrees)

Intermediate Level :

The following pie-chart shows the percentage distribution of the expenditure incurred in publishing a book. Study the pie-chart and the answer the questions based on it.

  1. If the difference between the two expenditures are represented by 18º in the pie-chart, then these expenditures possibly are

Solution:

Central angle of 18º = (18/360)x100% of the total expenditure

= 5% of the total expenditure.

From the given chart it is clear that:

Out of the given combinations, only in combination (d) the difference is 5% i.e.

Paper Cost – Printing Cost = (25% – 20%) of the total expenditure

= 5% of the total expenditure.

2.Royalty on the book is less than the printing cost by:

Solution:

Printing Cost of book = 20% of C.P.Royalty on book 

= 155 of C.P.Difference 

= (20% of C.P)  (15% of C.P) =55 of C.P.

Percentage difference =(DifferencPrinting Cost×100) %                                                                    = (5% of C.Printing Cost×100)  % = 25%.         

3. If 5500 copies are published and the transportation cost on them amounts to Rs. 82500, then what should be the selling price of the book so that the publisher can earn a profit of 25%?

Solution:

For the publisher to earn a profit of 25%, S.P. = 125% of C.P.

Also Transportation Cost = 10% of C.P.

Let the S.P. of 5500 books be Rs. x.

Then, 10 : 125 = 82500

x => x = Rs.(125×82500)/10= Rs. 1031250.

Therefore S.P. of one book = Rs. 1031250/5500= Rs. 187.50 .

4. If for a certain quantity of books, the publisher has to pay Rs. 30,600 as printing cost, then what will be amount of royalty to be paid for these books?

Solution:

Let the amount of Royalty to be paid for these books be Rs. r.

Then, 20 : 15 = 30600 : r => r = Rs. (30600×15)/20

= Rs. 22,950.

5. What is the central angle of the sector corresponding to the expenditure incurred on Royalty?

Central angle corresponding to Royalty = (15% of 360)º

= (15/100)x360º

= 54º.

Expert Level:

Study the following Two Pie charts and answer the questions based on them.

  1. If in 1998, the population of villages Y and V increase by 10% each and the percentage of population below poverty line remains unchanged for all the villages, then find the population of village V below poverty line in 1998, given that the population of village in 1997 was 30000.

Solution:

Population of village Y in 1997 = 30000 (given).

Let the population of village V in 1997 be v.

Then, 15 : 10 = 30000 : v => v = (30000×10)/15= 20000.

Now, population of village V in 1998 = 20000 + (10% of 20000) = 22000.

Therefore Population of village V below poverty line in 1998 = 58% of 22000

= 12760.

2. Find the population of village S if the population of village X below poverty line in 1997 is 12160.

Solution:

Let the population of village X be x.

Then, 38% of x = 12160 => x = (12160×100)/38 = 32000.

Now, if s be the population of village S, then

16 : 11 = 32000 : s => s =(11×3200)/16= 22000.

3. If the population of village R in 1997 is 32000, then what will be the population of village Y below poverty line in that year?

Solution:

Let N be the total population of all seven villages.then, population of village T below  poverty line= 465 of (215 of N) and 

Population of village Z below the poverty line = 42% of(11% of N)

 Required ratio = 46% of (21% of N)42% of (11% of N) 

= 46×2142×11 = 22000.

4. If the population of village R in 1997 is 32000, then what will be the population of village Y below poverty line in that year?

Solution:

Population of village R = 32000 (given).

Let the population of village Y be y.

Then, 16 : 15 = 32000 : y => y = (15×32000)/16= 30000.

Therefore Population of village Y below poverty line = 52% of 30000 = 15600.

 

 

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