If Lopez's flight is earlier than Germond's, which one of the following statements could be false?

Anna20 on March 5, 2021

Yes please - agree with the question above - I don't see the difference between C and D?

A, B and E are wrong because they must be true if the set up is

_ _ _ _ [R S T U] (copilots)
_ K _ _ [F G K L] (pilots)

We would fill in the above if L comes before G (L - G) and U and L must be paired together. F must be in spot one because G has F plus one other element go before it:

_ _ U _
F K L G

The diagram above rules out the following because they must be true (A) Simon's flight is earlier than Umlas's (B) Umlas is assigned to flight 3 and (C) Fazio's flight is earlier than Umlas's.

However, grateful if you could please clarify how to differentiate between C and D?

Thank you!

Baishak on March 12, 2024

It's seem to me that both C and D are correct. Can someone please explain why?????

Emil-Kunkin on March 16, 2024

C tells us that one of r and t must be before u. This must be true. U is third, so there must be at least one of r and T before U.

D does not have to be true, s could be after u.

C tells us that one of two things must happen, d tells us that one thing always must happen.