A new toothbrush, formed from two types of plastic, A and B, in an inj

A. Whether plastic B maintains stability after being in contact with other plastics

As we can see, passage is no where talking about stability of B. As argument is clearly about stability of A so we can discard this option as this option is only talking about stability of B and not A. REJECT

B. Whether plastic A reacts in a similar way when molded alone, or with a plastic other than B

This option clearly talks about stability of plastic A with various other plastics and also when it is molded separately. So from this option we can establish some thing about stability of plastic A like whether it goes well with other plastics or not, if it goes well then there must be some issues with B... like that. So this option looks good so we will keep this on hold.

C. Whether plastics other than A and B can be used in the injection-molding process

This option is talking about using some other material to be used in injection molding process.... which will not help in any way to establish stability of Plastic A. REJECT
D. Whether the new toothbrushes are intended for distribution to foreign retailers

This option is talking about distribution which is not related with stability of product. REJECT

E. Whether plastic A's instability can be corrected by the addition of a suitable chemical

This option talks about stability of A, but here it is talking about increasing the stability of A , which is not asked in question. REJECT

SO IMO B is the correct answer

CONCLUSION - Contact with plastic B is the cause of A's unstable nature

PRETHINKING -

IN WHAT SCENARIO - contact with plastic B is not the cause of A's unstable nature

GIVEN -

1) Toothbrush is made from 2 types of plastics - A & B
2) After 3 days, plastic A began to fall away

FALSIFICATION - Plastic A maybe susceptible to any other factor due to which it fell away

ASSUMPTION - Plastic A is not susceptible to any other factor due to which it fell away

ANSWER CHOICE ANALYSIS -

A) Being with other plastics won't help
B) CORRECT - Note that it is not inline with our prethinking but is another factor
C) Plastics other than A & B in injection moulding - Irrelevant
D) Retailer - Irrelevant
E) Correction of instability - Not relevant to the argument

A new toothbrush, formed from two types of plastic, A and B, in an injection-molding process, is being tested before mass production. It was noted that after three days of use, plastic A began to crack and fall away. It is clear that contact with plastic B is the cause for plastic A's unstable nature.

Which of the following would it be most useful to establish in order to evaluate the argument?


A. Whether plastic B maintains stability after being in contact with other plastics Incorrect

B's stability is not a fact

B. Whether plastic A reacts in a similar way when molded alone, or with a plastic other than B Correct

in this way we can found whether b is the reason or not

C. Whether plastics other than A and B can be used in the injection-molding process Incorrect

others plastics are irrelevant to argument

D. Whether the new toothbrushes are intended for distribution to foreign retailers Irrelevant

E. Whether plastic A's instability can be corrected by the addition of a suitable chemical Incorrect

we only need to know whether B is the only reason for A's unstable nature

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