How to Solve Data Sufficiency Questions Quickly

Why Data Sufficiency Questions are asked?

  • Data Sufficiency Questions are been asked to test whether you know the procedure to solve the question.
  • When you are asked to complete a task, initially you will collect all the related data/ information, using which your task can be completed. 
  • Here in Data Sufficiency, you are been tested whether you are aware of the data/information required to solve the question asked.
  • If you want to solve Data sufficiency questions quickly, you need not to derive the exact answer.
  • It is sufficient if you can able to analyze the given statements and find whether data given in the statements are sufficient to answer the question.

Let us discuss, How to solve Data Sufficiency with some Sample Questions. Each of the following questions has two statements. You have to decide whether data provided in the statements are sufficient to answer the question.

Options:

A. If the data in statement I alone are sufficient to answer the question, while the data in statement II alone is not sufficient to answer the question
B. If the data in statement II alone are sufficient to answer the question, while the data in statement I alone is not sufficient to answer the question
C. If the data either in Statement I alone or Statement II alone are sufficient to answer the question
D. I the data in both the statements I and II are not sufficient to answer the question
E. If the data in both the statement I and II are together necessary to answer the question.

Question / Answer

1. Who is richest among five friends (A, B, C, D and E)?
Statement I: A is richer than E and Poorer than D. E is only richer than C. Dis not the richest.
Statement II: D is poorer than B and richer than E, who is not the poorest.

Answer: Option A

Explanation:

From Statement I:

  • B >D>A>E>C
  • B is Richest
  • So, here Statement I is sufficient to answer

From Statement II:

  • B>D>E ( here, the richest person can be either A or C)
  • Statement II is not sufficient to answer
  • Therefore, Statement I alone Sufficient to answer.

2. What is the Perimeter of the Rectangular Plot?

Statement I: If Ratio between length and breadth is 7:3
Statement II: If Area of the plot is 525 sq.m

Answer: Option E

Explanation:
From Statement I:

  • L/B = 7/3
  • 3L = 7B
  • Statement I is not sufficient to answer

From Statement II:

  • Area = L * B = 525
  • Statement II is not sufficient to answer

Now let us combine data given in Statement I and II

  • 3L = 7B
  • L= (7/3)*B
  • L*B =525
  • (7/3)*B*B = 525
  • B² = (525*3)/7
  • B² = 225
  • B = 15
  • L = 525/15 =35
  • Perimeter = 2(L+B)
  • By substituting L and B in Perimeter formula we can obtain the answer.
  • You need not to obtain the exact value.
  • So, Both Statement I and II are needed to answer the question.

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