GRE Sample Test 4 Quantitative Reasoning 2

Quantity A cannot be precisely defined, but Quantity B can. The grape bag weighs 50 grams, and each grape weighs exactly 1 gram, so there must be 50 grapes in the bag. Quantity B is 50.
Now consider Quantity A. If every cookie in the bag is on the lighter end, weighing only 5 grams, then the number of cookies in the bag is 300 divided by 5, or 60. If, contrarily, the bag is full of the heaviest cookies in town, each weighing 15 grams, then there are 300 divided by 15, or 20, cookies in the bag. Thus, Quantity A is somewhere between 20 and 60, which means it could be less than, equal to, or greater than Quantity B. You have no idea which is the case, so pick (D).