CAT 2019 Question Paper | Quants Slot 1

CAT Questions

The importance that Arithmetic occupies in the CAT syllabus cannot be stressed enough. Here is another question from Time and Work. With good CAT Preparation, these arithmetic questions are easy pickings. The speed and accuracy with which these arithmetic questions are solved gives the edge to aspirants who are well prepared. Try solving this question. If you are unable to solve, ensure you spend enough time in your CAT Preparation journey on arithmetic topics. CAT previous year paper are a good place to start.

Question 15 : At their usual efficiency levels, A and B together finish a task in 12 days. If A had worked half as efficiently as she usually does, and B had worked thrice as efficiently as he usually does, the task would have been completed in 9 days. How many days would A take to finish the task if she works alone at her usual efficiency?

1. 18
2. 12
3. 24
4. 36

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Video Explanation

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Explanatory Answer

We know that A and B together would finish a task in 12 days
So, ----(1)
Now, if A works in half the efficiency and B works thrice as efficiently, the work gets completed in 9 days.
----(2)
Multiply (1) by 3
----(3)
Solving (2) and (3) we get,


A = 18 days

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The question is "At their usual efficiency levels, A and B together finish a task in 12 days. If A had worked half as efficiently as she usually does, and B had worked thrice as efficiently as he usually does, the task would have been completed in 9 days. How many days would A take to finish the task if she works alone at her usual efficiency? "

Hence, the answer is 18

Choice A is the correct answer.