Neat question - thanks for posting this one!
Here I think it's a matter of making the options concrete. We know that the order of bricks is:
Blue, Orange, Purple, Blue, Orange Purple
Statement 1 tells us that #24 is NOT Orange, so we know we have two options:
24 25 26* 27
B O P* B.....
or
P B O* P......
So we don't know - 26 could be purple or orange.
Statement 2 similarly limits us to two options, starting with #25 as Not Blue, so either Orange or Purple. The sequence is then:
25 26^ 27
O P* B
or
P B* O
Again, this isn't sufficient as #26 could be either purple or blue.
But taken together, we have:
St. 1: #26 is either Purple or Orange
St. 2: #26 is either Purple or Blue
The only color consistent with both statements is Purple, so we know that the 26th brick must be Purple, and therefore the statement is sufficient.
Brian Galvin
GMAT Instructor
Chief Academic Officer
Veritas Prep
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