Hi All,
We're told that a school district paid a total of $35 per desk for X desks and a total of $30 per table for Y tables. We're asked for the total amount that the district paid for these desks and tables. This DS question revolves around basic Arithmetic, but you don't actually have to do any math to answer it...
(1) The total amount the district paid for the y tables was $900.
The information in Fact 1 will help us to determine the value of Y (it's 900/30 = 30), but not the value of X. Thus, the answer to the question will change depending on what X is.
Fact 1 is INSUFFICIENT
(2) X = 90, and the total amount the district paid for the X desks was 3.5 times the total amount the district paid for the Y tables.
The information in Fact 2 will help to determine the total spent on the desks ($35 x 90, although you don't have to calculate that to know that it WILL be a specific number). We can then divide that number by 3.5 to find the amount spent on the tables (again, we don't have to calculate it; we know that we COULD - and that it will be a specific number). With the money spent on the desks + the money spent on the tables, we can definitively answer the question.
Fact 2 is SUFFICIENT
Final Answer: B
GMAT assassins aren't born, they're made,
Rich