Bunuel
The Official Guide For GMAT® Quantitative Review, 2ND EditionWhat were the gross revenues from ticket sales for a certain film during the second week in which it was shown?
(1) Gross revenues during the second week were $1.5 million less than during the first week.
(2) Gross revenues during the third week were $2.0 million less than during the first week.
Basically they want to know what x2*y2 = TR2, where all 2's denote "second week", x denotes tickets sold and y denots price per ticket.
1) uses different variables (x1, y1 and TR1), and only gives us a relation between TR1 and TR2.. Clearly insufficient
2) uses different variables (x3, y3 and TR3), and only gives us a relation between TR1 and TR3, clearly insufficient.
1 + 2, we know absolutely nothing about x2 or y2, we're only given some weak relationships among the revenues for three consecutive weeks.
So the answer is E