Understanding of the conditions in LG

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superhedy2011

Posts: 17
Joined: Thu Sep 22, 2011 6:33 am

Understanding of the conditions in LG

Could anyone help me to explain the meaning of the two sentences I've taken from the conditions of Logic Games:

1) She does not have any meetings in a row with F. (The stimulus talks about there are 7 meetings, each with one of the five foreign dignitaries: F, M, R, S, or T, among which 3 meetings are with F). OCT 2004, Questions 1-6

2) The site visited 3rd dates from a more recent century than does either the site visited 1st or that visited 4th. (5 sites are visited, which are discovered by F, G or O archaelogists and date from 8th, 9th, 10th century AD.) OCT 2004, Question 13-17
Here, "either ... or ..." means at least one or both? I understand from the answer that it means both, but why is that? Don't we take "either ... or ..." as "at least one" in LR?

Thanks!

HellOnHeels

Posts: 548
Joined: Sun Jul 31, 2011 8:19 pm

Re: Understanding of the conditions in LG

1) She doesn't have meetings with F back to back.

2) The site visited 3rd has to be from an earlier century than both the 1st and 4th. So if 1 and 4 are 9th, 3 has to be 10th. If 1 and 4 are from the 8th, then 3 could be from the 9th or 10th century. 1 and 4 cannot be from the 10th century, because then 3 couldn't be from an earlier century.

Hope this helps.

superhedy2011

Posts: 17
Joined: Thu Sep 22, 2011 6:33 am

Re: Understanding of the conditions in LG

But why "either ... or ..." here accounts for "both"? Not "at least one"? I got from LR bible that "either or" means at least one. If it is "at least one", then 1st could date from 8, 9 or 10th century, 3rd from 9 or 10th, 4th from 8,9 or 10th. Without any other conditions, the respective century for 1st, 3rd, 4th site could be, (8,9,8), (8,9,9), (8,9,10), (9,9,8), (10,9,8), (8,10,8), (8,10,9), (8,10,10), (9,10,8), (9,10,9), (9,10,10), (10,10,8) or (10,10,9), rather than only (8,9,8), (8,10,8),(8,10,9),(9,10,8),(9,10,9).

By the way may I ask why "in a row with F" means no meetings with F back to back? If it states as "in a row of F", that would be much better for me. Are these two the same? Thanks!

stephinmd wrote:1) She doesn't have meetings with F back to back.

2) The site visited 3rd has to be from an earlier century than both the 1st and 4th. So if 1 and 4 are 9th, 3 has to be 10th. If 1 and 4 are from the 8th, then 3 could be from the 9th or 10th century. 1 and 4 cannot be from the 10th century, because then 3 couldn't be from an earlier century.

Hope this helps.