In Banking and other competitive exams like IBPS Clerk, SBI Clerk, SSC CGL, SBI PO and IBPS PO, line graph problems are a staple. You can expect up to 5 questions based on line graph problems alone. These problems, like bar graphs form the the most basic Data Interpretation (DI) questions. They are often complicated by the use of multiple graphs. But if you use the simple techniques shown below, these problems become easy.
Let us look at a shortcut method to solve a certain type of line graph problems using an example. If we attempt to solve it with complete complicated calculations, we will end up wasting a lot of precious time. Remember that the examiners don’t expect you to solve everything on paper. They want to see if you are capable of applying your logic to evaluate the graph, eliminate options, and arrive at the answer through estimation.
Once you master this technique, we will, in subsequent articles, deal with more complicated sets of line graphs.
Example of Line Graph Problems
Directions: Study the following line graph carefully and give answers to questions that follow.
Total number of males and females in five different companies
Ques: The number of females from company A is approximately what percent of the total number of females in all the companies put together?
1) 21
2) 17
3) 23
4) 19
5) 15
Ans: 5) 15
Solution:
There are different approaches to find out the answer to this question.
First Approach:
We can simply take all values and calculate the answer. i.e. we will have to find out (females in A)/(Total females). This would be the long method. If we solve it at leisure, we could get an accurate answer. But given the time crunch we face during the exam, we are likely to commit errors.
Second Approach:
This approach rests on the assumption of blocks. It simplifies our calculations significantly.
Here In this graph, we assume 1 block to be equivalent to 500 employees each. So with this assumption, we can see that females in Company A would be 5.5 blocks. Similarly females in in Company B would be 8 blocks and so on.
We can use approximations as follows to arrive at the above:
≈15%
