It takes 4 weeks for a team of 5 professional Window Washers working

IMO, the ans is 'D'..

here's my opinion:

A) If an empire state building window is to be kept clean, it must be cleaned by a professional cleaner.
-- no where it's implied here..Hence, incorrect

B)The owner's demand for proper cleaning of all the windows will never be fulfilled.
--maybe if the owner uses more people, he would be able to meet the demand

C) If a team of 5 window washers cleans all the empire state building's windows in less than 4 weeks, some windows will not be properly cleaned.
--it maybe the fact the all windows are not properly cleaned. We are not discussing the quality of the work

D) In order to ensure that all of the Empire State Building's windows are clean, the owner must have his window washers work overtime.
--i think this is the correct ans from the start, the passage is time constant. i.e. 4 weeks, 5 workers, working hours...i think this is the correct ans.

E)Some Empire State Building windows must be cleaned more frequently than once every four weeks if they are to be kept clean.
--Nowhere its implied this..

OA please...

The most fatal word in D is "must". If D is true - you are assuming workers MUST work "overtime" What if the vendor increases the number of workers or uses more productive workers. D will fail.

you're right..i missed that part. but i still fail to understand why E should be the right option? can you please explain?

It takes 4 weeks for a team of 5 professional Window Washers working regular full time hours to completely clean every window of the Empire State building. The building's owner demands that all the windows always be clean.Yet even if the 5 washers work consistently throughout their regular work week,they will not be able to finish cleaning all the windows before some windows will need cleaning .

The preposition states that vendor is not efficient to complete the job in 4 weeks time with 5 pro workers. It means that lets say window A was cleaned sometime on Jan 1st. Then it will again require cleaning around Feb 1st. E is a paraphrase of the stimulus.

It takes 4 weeks for a team of 5 professional Window Washers working regular full time hours to completely clean every window of the Empire State building. The building's owner demands that all the windows always be clean.Yet even if the 5 washers work consistently throughout their regular work week,they will not be able to finish cleaning all the windows before some windows will need cleaning .


Which of the following statements as must be true on the basis of the statements above ?


A) If an empire state building window is to be kept clean, it must be cleaned by a professional cleaner. Incorrect, Out of scope!
B)The owner's demand for proper cleaning of all the windows will never be fulfilled.Incorrect, It can be fulfilled by adopting many other measures.
C) If a team of 5 window washers cleans all the empire state building's windows in less than 4 weeks, some windows will not be properly cleaned. Incorrect, Stimulus does not state this fact.
D) In order to ensure that all of the Empire State Building's windows are clean, the owner must have his window washers work overtime.CORRECT! If the 5 washers work consistently throughout their regular work week,they will not be able to finish cleaning all the windows before some windows will need cleaning which is why working overtime might just solve the cleaning problem.
E)Some Empire State Building windows must be cleaned more frequently than once every four weeks if they are to be kept clean. Incorrect, Out of scope

I think the answer is Clearly E.

D) is way out of scope. Will working overtime definitely mean the windows stay clean? What if working overtime makes the washers less accurate in their cleaning? What if overtime is still not enough? The owner may need to hire more people? We have no information on the effectiveness of overtime working. There's no way that D MUST BE TRUE right?

E) SOME windows need to be cleaned more often than 4 weeks. This is a fact. This Must be true.

Can an expert please look at this?

nightblade354

MikeScarn,

This is a Kaplan question. Kaplan BLOWS. This a repeated theme: Kaplan questions having answers that cannot live up to an official GMAT answer. If (D) said "the windows are clean at the same time" it would be correct. As stated, (D) cannot be correct. Further, (E) is not supported either. If (E) said during a regular-hour work week, then (E) would be correct. But this is not stated either. This question should be avoided.

abhishekdadarwal2009, what if overtime is worked? This statement completely destroys (C) and is why it is not the answer. We are only told about REGULAR hours.

Horrible question, so please do not feel flustered by it.

I goes D.

The total hours to clean properly the building is 4 weeks for all building. If the productivity is the same, and some windows need cleaning again (because they will get dirty after 4 weeks), overtime is required.
Frequency is one solution but not a must, if some windows are cleaned frequently, they will not need cleaning

Is it possible to put some sort of warning tag on the question and/or retire it?

It seems like it is creating quite some confusion among the community...

Arro44,

I tagged it as poor quality/questionable OA. Short of my post, there is little I can do aside from letting it play out.

A) If an empire state building window is to be kept clean, it must be cleaned by a professional cleaner.
not mentioned
B) The owner's demand for proper cleaning of all the windows will never be fulfilled.
hire more people ..or let workers work overtime
C) If a team of 5 window washers cleans all the empire state building's windows in less than 4 weeks, some windows will not be properly cleaned.
not true ..work overtime
D) In order to ensure that all of the Empire State Building's windows are clean, the owner must have his window washers work overtime.

I chose this one ...but after a bit of study ,i think this one is flawed .... the boss could easily hire more people ..since this option doesn't have any premise to limit the number of workers

E) Some Empire State Building windows must be cleaned more frequently than once every four weeks if they are to be kept clean

This option has to be true ... remember ..5 ppl work full time for 4 weeks to clean every window ..but before they could even finish , some of the windows that has been cleaned before will need to cleaned again ... = some windows need to be cleaned less than every 4 weeks

Kaplan OE :

This is an Inference question because it directly asks for something that "can be correctly inferred."

Untangle the Stimulus:

It takes four weeks for the team of five washers working full-time to clean every window. Even if the five washers work consistently throughout the regular week, they won't finish cleaning before some windows again need cleaning.

Predict the Answer:

If any given window can be revisited four weeks later, yet some of them already need cleaning, then some windows won't stay clean if attended to only once every four weeks. They get dirty more quickly than this.

Evaluate the Choices:

(E) matches the prediction and is correct.

(A) is unsupported. The stimulus mentions how long it takes for professional window washers to clean all the windows, but never says that only professional window washers can clean them (however likely that may seem).(B) is wrong because there's no reason why the owner's demand couldn't be fulfilled by having 2 teams of 5 washers or by having one team work overtime. (C) is tempting because the stimulus states that one team would need 4 weeks to properly clean every window. However, it also states that this is if they're working regular hours; one team working overtime might be able to properly clean all the windows in less than 4 weeks. Contrary to (D), it may be that the owner could hire multiple teams, rather than have one team work overtime.

OA in original posting in GC not matching with Kaplan OE...

Moderators may please check..

mikemcgarry, GMATNinjaTwo, GMATNinja, broall, nightblade354

OA updated to (E). But I stand by my comment that it is not a strong question.

-- Mod Nightblade

nightblade354

I totally agree with you.

Posted from my mobile device

A) is not correct it says If an empire state building window is to be kept clean, it must be cleaned by a professional cleaner.---nothing to this effect mentioned in argument

B) is not correct it says The owner's demand for proper cleaning of all the windows will never be fulfilled.---he can employ more people

C) is not correct it says If a team of 5 window washers cleans all the empire state building's windows in less than 4 weeks, some windows will not be properly cleaned.---- can't infer from given information

D) is not correct it says In order to ensure that all of the Empire State Building's windows are clean, the owner must have his window washers work overtime.----if by working overtime workers are able to clean building in 3 weeks but some windows get dirty everyday then this won't be true

E) is correct it says Some Empire State Building windows must be cleaned more frequently than once every four weeks if they are to be kept clean.---- true because if after cleaning all windows in a period of 4 weeks , if building is not fully clean then some must get dirty before next round of cleaning