My five-year-old identical twins wear matching clothing.

I still don't get why it's B.... I thought it was D?

Whenever you are stuck in a CR assumption question,
considering you have narrowed it down to 2 choices negate the answer choice.
The correct option will make your conclusion invalid

In the following example,
Conclusion : WAVE cleans better than my regular laundry detergent.

You are down to 2 choices

(B) The shirt laundered in the regular laundry detergent was not significantly less clean than the other shirt before being laundered.
Negate it, If the shirts were not in the same condition to begin with, that is,
if the shirt laundered in regular laundry detergent was cleaner to begin with, the conclusion will not hold valid.
Because a cleaner shirt will come out cleaner after a wash.

(D) Clothes washed in WAVE laundry detergent will come out cleaner than clothes washed in any other brand of laundry detergent.
Negate it and it will not damage to conclusion to that extent.
In this choice, the WAVE laundry detergent being/ not being better than other brand of
laundry detergent is not going to damage the conclusion to that extent.

We have a clear winner(Option B)

Same here.
I feel that these are typical GMAT-traps that needs to be looked out for.

Hee hee. Such day to day life question. B it is, if one of the kids' shirt was dirtier to begin with (compared to the other cleaner one) then of course WAVE would win in terms of demonstrating 'cleans better'

My five-year-old identical twins wear matching clothing. I washed two of their soiled matching shirts, one in my regular laundry detergent, and one in new WAVE laundry detergent. The shirt washed in WAVE came out cleaner than the other shirt, so WAVE cleans better than my regular laundry detergent.
Which of the following is an assumption on which the argument in the advertisement depends?

The conclusion is WAVE cleans better than regular detergent as the shirt washed in WAVE came out cleaner than the other shirt. Now we need to find the assumption by reading question stem again.


(A) Five-year-old identical twins tend to soil their clothes more noticeably than do other children of the same age.
This has nothing to do with the conclusion..Out of scope.

(B) The shirt laundered in the regular laundry detergent was not significantly less clean than the other shirt before being laundered.
This option says that both the shirts were more or less equally dirty. So, this seems to be a good assumption. As if we know that the test parameter is same then which detergent is a winner. There might be other assumptions though like washing conditions, whether both clothes were cleaned by same person or machine etc.

(C) A soiled shirt laundered on a regular basis in the same laundry detergent will come out equally clean each time it is laundered.
This is also a good option, but not better than B as it assumes that the same laundry detergent will give same result in each wash. So, if the shirts are in same condition, and the laundry detergent result doesn't vary in each wash we can decide which detergent is better. So, this assumption comes into picture only after assumption in B is correct.

(D) Clothes washed in WAVE laundry detergent will come out cleaner than clothes washed in any other brand of laundry detergent.
This assumption is not related to the conclusion of the argument. Because to verify this we are doing cleaning test but the question stem is all about the experiment and not why experiment is being conducted. So we need to find the assumption which is going on during the experiment.

(E) Most pairs of young identical twins tend to wear matching clothing.
This is totally out of scope.

Answer B

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