Question


Debater: The average amount of overtime per month worked by an employee in the manufacturing division of the Haglut Corporation is 14 hours. Most employees of the Haglut Corporation work in the manufacturing division. Furthermore, the average amount of overtime per month worked by any employee in the company generally does not fluctuate much from month to month. Therefore, each month, most employees of the Haglut Corporation almost certainly work at least some overtime.

The debater’s argument is most vulnerable to criticism on which of these grounds?

(Because of copyrights, the complete official question is not copied here. You can access the question here: GMAT Club)

Difficulty: Medium

Accuracy: 71%

Based on: 7111 sessions

Solution


The Story

Debater: The average amount of overtime per month worked by an employee in the manufacturing division of the Haglut Corporation is 14 hours. – Avg. O/T of an employee in the manufacturing division = 14 hours/month

Most employees of the Haglut Corporation work in the manufacturing division. – Manufacturing division has >50% employees of the company.

Furthermore, the average amount of overtime per month worked by any employee in the company generally does not fluctuate much from month to month. – Avg. O/T per month of any company employee doesn’t fluctuate much. (Notice: the first statement talks about the average O/T worked by a manufacturing division employee, whereas this one talks about the average O/T by any employee in the company.)

Therefore, each month, most employees of the Haglut Corporation almost certainly work at least some overtime. – Conclusion: >50% employees of the company work overtime – each month.

Author’s logic:
Since the division that has >50% of the company’s employees works an average of 14 hours of overtime per month and the average amount of overtime worked by the people in the company does not fluctuate much (basis), most employees of the company work at least some overtime per month (main point).

Gap(s) in logic:

  1. Maybe a fraction of employees in the manufacturing division work overtime, but they work insane hours of overtime bringing the average for the entire division to 14 hours/ month. Thus, it isn’t necessary that every employee of the manufacturing division works overtime. For that matter, it isn’t even necessary that most of the manufacturing division employees work overtime.

    Say, the manufacturing division has ten employees.
    Now, it is possible that of the ten employees, only two work overtime
    And, the two employees work 70 hours of overtime a month each, bringing the average monthly overtime of the division to 140/10 = 14 hours/ month
  2. We do not know whether the other divisions work any overtime at all. So, maybe the employees of the manufacturing division who work overtime are the only overtime workers in the company.

Question Stem

The debater’s argument is most vulnerable to criticism on which of these grounds?

Prediction:
In line with the above gap analysis.

Answer choice analysis


Answer Choice: A

Incorrect

Selected by: 6%

‘the manufacturing division is a typical division of the corporation with regard to the average amount of overtime its employees work each month’
Does the argument believe that a regular division of the company works close to 14 hours O/T per month – just the way the manufacturing division does?
No.
The conclusion isn’t that the company’s overall average overtime is close to 14 hours/ month. In the conclusion, the author claims that most employees work at least some overtime. The overtime worked by the other divisions need not be close to the overtime of the manufacturing division for the argument to make sense. That the manufacturing division is a typical division with regard to overtime isn’t something that the argument takes for granted.


Answer Choice: B

Incorrect

Selected by: 8%

The conditional in the statement: If each employee works a certain average amount of overtime, then the manufacturing division employees also work approximately the same hours of overtime.

The argument is not based on such a conditional. We are given in the passage that the average overtime of a manufacturing division employee is 14 hours. This figure is not based on the overtime worked by every employee of the company.


Answer Choice: C

Incorrect

Selected by: 5%

What does the statement mean?

The argument confuses one claim with another.

Let’s say the claims are Claim 1 and Claim 2.

Claim 1:
‘a claim from which the argument’s conclusion […] would necessarily follow’
Claim 1 → conclusion (necessarily)

Claim 2:
‘a claim that would follow from the argument’s conclusion only with a high degree of probability’
Conclusion → Claim 2 (probably)

Does the argument confuse any such claims? In fact, does the argument even have two such claims to confuse? There certainly is no claim that follows the argument’s conclusion. So, the question of confusing such claims doesn’t arise.

The key to understanding why this answer choice was incorrect lay in reading the answer choice patiently and precisely to understand what the statement means. Once we do that, we can see that the argument does not have any such confusion.


Answer Choice: D

Correct

Selected by: 71%

This option is in the line with our prediction.
Let’s say total #employees = 100
Say, manufacturing division has 60 employees.
For average O/T of 14 hours, total O/T of the manufacturing division = 14 x 60 = 840 hours
Say, this O/T is worked by 30 employees (I choose a number less than half of 100).
So 840/30 = 28 hours O/T are worked by 30 employees and 0 hours O/T worked by the rest of the manufacturing division.

Also, say the employees not in the manufacturing division work 0 hours O/T.

Thus, only 30 employees (out of 100) work overtime.

So, even if a certain amount of overtime (14 hours) is worked by the members of some group (manufacturing division), many members of that group may work no overtime at all. And thus, the conclusion that most employees of the company almost certainly work at least some overtime need not be true.

This is the possibility the argument overlooks.


Answer Choice: E

Incorrect

Selected by: 11%

‘even if most employees of the corporation work some overtime each month, any one corporate employee may, in some months, work no overtime’

Does the argument overlook this possibility?

The argument deals with averages. The author concludes that most employees work at least some overtime. The conclusion could very well be made keeping in mind that some employees might work no overtime. The argument about average hours of overtime can be made even if some employees work no overtime in some months. The author does not overlook this possibility.

Additional Notes


Although only 5% test takers choose option C as the correct answer on GMAT Club. However, I find that the reasoning is incorrect for a much higher percentage. And the typical reason is that many students do not even understand what the statement is saying.
Even if you got the answer correct, it makes sense to spend time to understand and confirm your reasons behind eliminating all incorrect answers as well.

If you have any doubts regarding any part of this solution, please feel free to ask in the comments section.

Anish Passi

GMAT Coach

With over a decade of GMAT training experience, top 1 percentile scores on the CAT and GMAT, Anish is one of the most qualified GMAT coaches in India. He has founded and served as Director in two ed-tech startups in the past. An alumnus of IIM Ahmedabad and McMaster University, Canada, he strongly believes in the right way of learning, and in learning to grow and not just to get a score, an admission or a job. Anish offers private tutoring and live-online classroom courses. His sessions are often sprinkled with jokes that only he finds funny (you’ve been warned). To connect with him, write to him at a@TheGMATCo.com

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