For most people, the Problem Solving questions on the GMAT are the ones that are most familiar to them in the beginning but sometimes they end up prefering Data Sufficiency more later on. Sure, it's confusing at first, but then they like the idea of not having to do many calculations, if any, to arrive at the answer. But is it always necessary to do many calculations in Problem Solving?
The name seems to indicate that there is a lot of "solving" in these questions. But remember that the goal of the GMAT is not to see if you are a human calculator. Instead, Problem Solving questions usually lend themselves to tricks and shortcuts such as simplifying, testing numbers, eliminating answer choices and working backwards.
This is powerful because what I see most people do is to work with the numbers and variables given and keep on operating until they reach a solution, and only then do they look up to the answer choices.
Out of all the strategies for solving problems quicker, I think the one that is most overlooked is to use the answer choices. Now, I know why many students are fearful to use this strategy: they have been conditioned in Data Sufficiency that trying only one number is not always a good idea, you have to try two or more to be sure. But what makes Problem Solving special is that there is only one possible answer! It cannot be A and C at the same time.
Here is an example:
A store currently charges the same price for each cup that is sells. A person would be able to buy 5 fewer cups for $60 if the current price of each cup were to be increased by $2. What is the current price of each cup?
The first step is to set up our equation using x for price and y for number of cups:
The next step would be to solve for x and y right? The problem is that it is going to result in a messy quadratic equation. So the strategy will be to use the answer choices. Remember that we are looking for x (the price of each cup). So the value of x must give the same value of y in both parts of the equation.
A) \(x=3\) makes \(y=20\) in the first equation and \(y=17\) in the second equation. INCORRECT.
B) \(x=4\) makes \(y=15\) in the first equation and \(y=15\) in the second equation. CORRECT!
Do we need to test the other answer choices? No! because there can only be one correct answer choice. So we have arrived at the answer just trying two values. Even if the correct answer was in E, it would still be less mentally taxing than doing the quadratic equation for most people.
To summarize, treat the answer choices as "extra data" in Problem Solving questions. Look at them before operating to see which clues they give you. Using the answer choices can take less time and leave you with more energy for other problems.
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