Hi All,
Questions on the GMAT are always carefully worded, so you have to respect that level of detail and do the necessary work to get the answer to the question THAT IS ASKED. In DS questions, even with the same information, a difference in the wording of the question can lead to a different correct answer.
Here, we're given the price of each shovel ($14) and each rake ($9) and we're asked for the TOTAL COST of ALL the shovels and rakes purchased in the store.
To figure out TOTAL COST, we need to know the number of shovels and the number of rakes.
The math involved in solving this problem has already been explained by gmatblackbelt, so I won't rehash that here. Instead, consider how the answer changes when I just change the question.
What if the prompt asked: "Is the total cost of the shovels greater than the total cost of the rakes?" (Hint: the answer would NOT be C).
How about if it asked: "Is the combined cost of the shovels and rakes greater than $100?" (Hint: the answer is also NOT C.)
The math involved in most DS questions is not difficult, which is why DS questions aren't really there to test math skills. DS questions test you on a number of other skills that matter though, including organization, accuracy, attention-to-detail, thoroughness, the ability to PROVE that you've correct, etc. Don't let pride get in the way of picking up easy points on the GMAT - take the notes, do the necessary work and you can pick up all of these easy points.
GMAT assassins aren't born, they're made,
Rich