Suppose the crew had cleaned Fourth Street on Tuesday afternoon instead of on Tuesday morning, but all other conditio...

HananFrancis July 27, 2019

Confused on Question 6 set up

Why could we not add street 1 and 3 to the binary of 2 and 5 on Thursday and Friday? There are no rules that state otherwise. Unless I have missed something

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Ravi July 27, 2019

@HananFrancis,

The board for this question is

am _ _ _ 7 x
pm 8 4 x _ _
M T W R F

2nd and 5th get cleaned on afternoons, so they occupy Thursday and
Friday (and can switch between them).

This means that 6 must go Wednesday morning since that's the only
remaining spot after 4 (and 6 must be cleaned after 4).

am _ _ 6 7 x
pm 8 4 x 2/5
M T W R F

This is why (B) could be false. 2nd street could be cleaned before 5th
street, or 5th street could be cleaned before 2nd street.

Does this make sense? Let us know if you have any more questions!

idonije September 17, 2021

Can someone please explain why 6 must appear after 4? Its not an original rule so I don't see why its now applied.

KiaBrodersen November 1, 2023

Hey Alexander, I'm not an instructor, but 6 coming after 4 is an original rule:

It cleaned Fourth Street before Sixth Street and after Eighth Street.