As on many DS problems, here you can save yourself time by using reasoning rather than immediately calculating.From the prompt, we know the profit per poster is 18 - 10 = $8
The profit per banner is 30 – 16 = $14
So the question can be restated as:
8p + 14b > $1,200 ?
We also know the posters and banners add to 110:
p + b = 110
Statement 1:This tells you that 1p + 4b = 290
Now you have two different simultaneous equations with the same two variables. A system of this type can always be solved, giving you values for p and b.
Plugging these values into 8p + 14b will result in a total dollar figure. Either this amount is more than $1,200 (a definite YES) or it isn’t (a definite NO). No need to actually calculate.
Sufficient.Statement 2:If the studio sold more banners than posters, a YES is clearly possible. 100 banners at $14 per banner, for example, would give you $1,400 profit, which is already more than $1,200.
But can you get an answer of NO? Try the other extreme. If there were an equal number of posters and banners, the weighted average profit per unit would be $11 (right in the middle of $8 and $14). Then, $11 X 110 = $1,210, which is also more than $1,200. The answer must be YES.
Sufficient. The answer is D.
(Note that technically, there must be
more banners than posters. So the total actually must be even more than $1,210.)
Remember to reason your way through DS problems before diving into calculations, and you can save yourself time and potential frustration.