Q6

[skapur777]

Confused by this question.

I didn't think B was a primary purpose, they just both happened to mention it. I thought it was quite relevant in passage A but not soo much in passage b.

Also, why is D incorrect? because explanation of why certain drilling muds are used are only mentioned in like...two lines? (line 40 and 47 probably?)

[bbirdwell]

The question is asking us for "a" primary purpose, meaning there are at least a couple of "primary purposes" for each passage.

Passage A:
p1 - definition/purpose of drilling fluids
p2 - composition of drilling fluids
p3 - they're hard to study because of the variety of formulations

Passage B:
p1 - discharges are main environmental concern
p2 - one type of mud: composition, toxicity, discharge
p3 - another type: composition, toxicity, discharge

Where's the overlap? Composition is really the only categorical overlap here because drilling "fluids" aren't really defined in Passage B like they are in A.

(A) nope. Passage A doesn't do this.
(B) yep. They both do that, and the composition of the fluids is important to the point each author makes.
(C) nope. Passage A doesn't do this.
(D) nope. Passage A does this in its first paragraph, while Passage B does not. You mentioned lines 40 and 47. However, these lines merely tell us that WBM is used in shallow and that OBM is used in deep. It does not actually tell us why this is the case. In other words, Passage B answers the question "Which mud?" but it does not answer the question "Why mud?"
(E) nope. Passage A mentions a difficulty in studying, not regulating.