Shipping Clerk: The five specially ordered shipments sent out last wee

100% E and OA is E

Since we know that 1 of the box wasn't building material that means one of the box was not sent on Friday. The reason is all the boxes sent on Friday was building material. Also, no shipment afterward Friday, so it has to be before Friday.

C is the OA.

PASSAGE ANALYSIS

Comcorp Shipping Clerk: Last week, no shipments of building supplies were sent out on Friday.
This statement tells us that Comcorp did not send out any shipments of building supplies on Friday last week. So, it could have sent out shipments of other supplies on Friday—but none of the Friday shipments consisted of building supplies.
The five specially ordered shipments sent out last week were sent out on Thursday, and each of those specially ordered shipments consisted entirely of building supplies.
This statement tells us that there were only five shipments sent out last week that were specially ordered. The use of ‘the’ before ‘five specially ordered shipments’ tells us that there were no more than five specially ordered shipments sent last week. These five shipments were all of building supplies and were all sent on Thursday.
Four shipments were sent to Truax Construction last week, none of which consisted of building supplies.
This part tells us that Comcorp sent four shipments to its customer, Truax Construction, last week. None of Truax’s shipments consisted of building supplies.
PRE-THINKING

If the shipping clerk’s statements are true, which of the following must also be true?
The question stem asks us to identify a statement that can be inferred from the given information.
First, let’s identify all the information given in the passage about shipments sent by Comcorp last week.
No building supplies were sent on Friday.
All five specially ordered shipments were sent on Thursday, and all five consisted only of building supplies.
Four shipments were sent to Truax, and none of these consisted of building supplies.
What can we derive from this information? First, from (2), we can infer that there were no special orders sent out last week for shipments other than building supplies. We can also infer from this statement that there were no specially ordered shipments sent on any day last week other than Thursday.
Also, from the information given about Truax, we can infer that no specially ordered shipment was sent to Truax last week, since none of its shipments consisted of building supplies, and all the specially ordered shipments consisted of building supplies.
ANALYSIS OF OPTION STATEMENTS

A. All of Comcorp’s shipments of building supplies last week were specially ordered.
This option is incorrect. The passage says that all five specially ordered shipments sent last week consisted of building supplies. This does not mean that only five shipments of building supplies were sent last week. Other shipments of building supplies that were not specially ordered could have been sent last week.
B. None of Comcorp’s shipments sent on Friday of last week was sent to Truax Construction.
This option is incorrect. The only information given in the passage about Friday is that none of Friday’s shipments consisted of building supplies. Since none of the shipments sent to Truax last week consisted of building supplies, one or more of other shipments could have been sent to Truax on Friday.
C. None of the shipments sent by Comcorp to Truax Construction last week was specially ordered.
We know from the passage that all five specially ordered shipments sent last week were for building supplies. Since none of the four orders sent to Truax consisted of building supplies, it can correctly be derived from the passage that none of the specially ordered shipments was sent to Truax. This is the correct answer.
D. None of Comcorp’s shipments sent on Thursday of last week was sent to Truax Construction.
This option is incorrect. The passage does not tell us how many shipments were sent on Thursday. All five specially ordered shipments, which consisted of building supplies, were sent on Thursday. But there could also have been other shipments sent on Thursday that were not specially ordered, and one or more of these could have been sent to Truax.
E. All of Comcorp’s shipments of building supplies last week were sent out on Thursday.
This option is incorrect. We know from the passage that all five specially ordered shipments sent last week were sent on Thursday, and that all of these five shipments consisted of building supplies. This does not mean that only five shipments of building supplies were sent on Thursday. Other shipments of building supplies that were not specially ordered could have been sent on Thursday.

Courtsey: e-gmat

Kindly request a systematic way for solving this question. Also a detailed explanation of the answer choices please. Thank You.

Premise: Four shipments were sent to Truax Construction (TC) last week, only three of which consisted of building supplies... (1)
Inference from (1): Exactly one shipment to TC did not consist of building supplies - Name this shipment X .... (2)

Premise: all of the shipments that were sent out on Friday consisted entirely of building supplies.. (3)
Conclusion from (2) ad (3): Shipment X was not among the shipments sent on Friday... (4).

(4) leads to option E: shipment X was sent before Friday.

My answer: E (Awaiting OA)

Shipping Clerk: The five specially ordered shipments sent out last week were sent out on Thursday. Last week, all of the shipments that were sent out on Friday consisted entirely of building supplies, and the shipping department then closed for the weekend. Four shipments were sent to Truax Construction last week, only three of which consisted of building supplies.

If the shipping clerk’s statements are true, which of the following must also be true?

A. At least one of the shipments sent to Truax Construction last week was specially ordered. -We don't know this from the passage. We are just told that 3 building and 1 other shipment were sent to Traux.
B. At least one of last week’s specially ordered shipments did not consist of building supplies. -We don't know this either. We are NOT told that all the building supplies were shipped on friday. We are just told that on friday all the shipments were building supplies.
C. At least one of the shipments sent to Truax Construction was not sent out on Thursday of last week. -We don't know this either. Maybe all the 4 were sent out on thursday.
D. At least one of the shipments that were sent out on Friday of last week was sent to Truax Construction. -We just know that on friday all the shipments consisted of building supplies. We are not told that all the building supplies were shipped on friday.
E. At least one of the shipments sent to Truax Construction last week was sent out before Friday. -Correct.

Correct answer: E. At least one of the shipments sent to Truax Construction last week was sent out before Friday.

Of TC's four shipments, three were building supplies. Because entire shipments sent out on Friday were building supplies, one of TC's shipments that was not building supply must have shipped NOT on Friday, or before Friday.

Argument analysis
The five specially ordered shipments (SoS) sent out last week were sent out on Thursday. - Five SoS sent out last Thursday. It doesn't say that only SoS were sent out on Thursday, so it's possible that some non-SoS may also have been sent on Thursday.
Last week, all of the shipments sent out on Friday consisted entirely of building supplies - Friday ONLY building materials and no other materials.
The shipping department then closed for the weekend - weekend no shipments.
Four shipments were sent to Truax Construction last week, only three of which consisted of building supplies. - 3 building materials may or may not have been sent on Friday (maybe they were sent on Thursday), but one non-building material has to go any day before Friday, as Friday is only building materials

Option elimination

A. At least one of the shipments sent to Truax Construction last week was specially ordered. We don't know. Might-be-true type of wrong option.

B. At least one of last week’s specially ordered shipments did not consist of building supplies. We don't know. Might-be-true type of wrong option.

C. At least one of the shipments sent to Truax Construction was not sent out on Thursday of last week. We don't know. Might-be-true type of wrong option.

D. At least one of the shipments that were sent out on Friday of last week was sent to Truax Construction. We don't know. Might-be-true type of wrong option.

E. At least one of the shipments sent to Truax Construction last week was sent out before Friday. 100% correct per the argument analysis.