Quant Is ALL Problem Solving Now. Good. TEST THE ANSWERS.

By EMPOWERgmat on February 20, 2024

Here is a scene I watch play out every single week. Someone opens a Quant question, sees a ratio and a couple of unknowns, and starts writing x's and y's. Two equations. Then a substitution. Then a sign error. Three minutes later they have an answer that isn't one of the five choices. So they start over.

Meanwhile, the correct answer was sitting right there on the screen the whole time. All they had to do was try it.

That is NOT a math problem. That is a strategy problem. And on the GMAT Focus Edition, it's the most fixable strategy problem you have.

The test just handed you a gift

On the Focus Edition, the Quantitative Reasoning section is 21 questions in 45 minutes, and every one of them is Problem Solving. Problem Solving means a regular multiple choice math question: a prompt, a question and five answer choices, one of them correct. Data Sufficiency now lives in the Data Insights section, and geometry is gone from the test entirely. You can confirm the layout on GMAC's GMAT exam format page.

Stop and think about what that means. EVERY Quant question you see on Test Day comes with five possible answers attached. One of them is right. You don't have to build the answer from nothing. You just have to find it.

Most people treat those five choices like decoration. They solve first and peek at the answers at the end to see if they "got it." That's backwards. The answers are information. Often they're the fastest route you have.

I'll bet that at least one Quant question you missed in your last practice set had an answer you could have checked in under a minute. Go look. I'll wait.

Why plugging in beats your algebra

Algebra asks you to do a lot of steps in a row, perfectly, under time pressure. Every step is a chance for a little mistake: a dropped negative, a flipped fraction, a wrong line copied from earlier. TEST THE ANSWERS replaces all of that with simple arithmetic you check against the prompt.

Here's the method:

Read the question and write down what it's actually asking for. Not what you assume. What it ASKS.
Numbers in the choices are usually listed in order, small to large. Start with the middle one, C.
Run C through the story in the prompt, step by step, on paper.
If it works, you're done. If it doesn't, ask whether you need a bigger number or a smaller one. That usually knocks out two more choices at once.

Notice that you're never solving an equation. You're checking a story. That's a very different job, and it's a lot harder to mess up.

Try it

A jar holds only red and blue marbles. There are 10 more blue marbles than red marbles. If 5 red marbles are added to the jar, the ratio of red marbles to blue marbles becomes 3 to 4. How many red marbles were in the jar at first?

Show the answer

Notes first. Write: Blue = Red + 10. Add 5 red. New Red : Blue = 3 : 4. Asked for: red at FIRST.

Test C, 15. Red starts at 15, so blue is 25. Add 5 red and red becomes 20. The ratio is 20 to 25, which is 4 to 5. We need 3 to 4. Is 4/5 too big or too small? 4/5 = 0.8 and 3/4 = 0.75, so it's too big. Red is too large compared to blue. Go smaller.

Test B, 10. Red starts at 10, so blue is 20. Add 5 red and red becomes 15. The ratio is 15 to 20, which is 3 to 4. That's it.

The answer is B.

The trap: people who set up the algebra often solve for the red marbles AFTER the 5 are added, which is 15. That's answer C, sitting right there waiting for them. Writing "asked for: red at FIRST" in your notes is what saves you. Total work: two quick checks, no equations.

If you want to see why the translation step matters so much, read translating word problems before you calculate. Testing the answers only works if your notes capture the story correctly.

A person standing in front of five closed doors in a row, having already checked the middle door, now confidently walking through the door just to its left. — You don't build the answer. You check the ones you were given.

When the answers have letters in them, TEST VALUES

Some Problem Solving questions have variables in the answer choices instead of numbers. Same idea, slightly different tool. You pick simple numbers for the variables, figure out the answer the prompt wants, then see which choice matches.

Try it

A worker earns d dollars per hour for the first 40 hours she works in a week, and 1.5 times that hourly rate for every hour beyond 40. If she works h hours in a week, where h is greater than 40, how many dollars does she earn that week?

1.5dh
40d + 1.5dh
40d + 1.5d(h − 40)
1.5d(h − 40)
60d + dh

Show the answer

Pick easy values. Say d = 10 and h = 50. Write them down.

Find the target. First 40 hours at $10 is $400. The other 10 hours pay $15 each, which is $150. Total: $550. Circle 550.

Check every choice. Not just until one works. ALL of them.

(A) 1.5 × 10 × 50 = 750. No.
(B) 400 + 750 = 1,150. No.
(C) 400 + 15 × 10 = 400 + 150 = 550. Yes.
(D) 15 × 10 = 150. No.
(E) 600 + 500 = 1,100. No.

The answer is C.

The trap: choice B. It looks right if you're thinking "base pay plus overtime" fast, but it pays overtime on ALL h hours instead of just the extra ones. And D is what you get if you forget the first 40 hours exist. Testing values catches both in seconds.

Why check all five? Because sometimes two choices both hit your target by luck. If that happens, pick new values and test only the survivors. It's cheap insurance.

The mistakes I see every week

Starting with A and grinding forward. You might test four choices before you find it. INSTEAD: start with C. When it fails, the direction you need kills two more choices at once.
Testing answers in your head. This is the one that drives me nuts. You "know" 15 plus 5 is 20, so you don't write it, and then you compare the wrong two numbers. INSTEAD: every test gets its own short line on your pad. The whole point is to avoid little mistakes, so don't invite them back.
Forgetting what the question asked. You test a choice, it fits the story, and you pick the wrong quantity anyway, like in the marble question. INSTEAD: before you test anything, write "asked for:" and the exact thing.
Saving plug-in for "when I'm stuck." If you only use it as a last resort, you'll use it slowly and badly on Test Day. INSTEAD: train it as a FIRST option on every question where it could work, so it's automatic.
Picking ugly values. Choosing d = 7.3 turns a 30 second check into a mess. INSTEAD: use small, friendly numbers like 2, 5, 10 or 100, and avoid 0 and 1 unless the question invites them.
Thinking it's "cheating." Some strong math students refuse to plug in because it feels beneath them. That's pride, and pride is a ceiling. The GMAT gives points for correct answers, not for elegant ones. INSTEAD: decide what you want MORE: to look like a mathematician or to score higher.

How to train the habit

Knowing this method and USING it under pressure are two different things. You have 45 minutes for 21 questions, which works out to a little over 2 minutes per question on average. You won't have time to debate which method to use. The choice has to be automatic.

So train it like a skill, not a fact:

Redo, don't just do. Go back to Problem Solving questions you already got right using algebra. Solve them again by testing the answers or testing values. Time both methods. Compare.
Ask one question on every review. Before you read any explanation, ask: "Could I have tested the answers here?" If yes, do it right then.
Learn the shortcuts that help you eliminate. Some topics let you cross out choices before you test anything. For example, in weighted averages, the answer is closer to the bigger group, so two or three choices are often dead on sight.
Practice with real questions. GMAC's official practice materials show you how the choices are built on the actual test, which is exactly what you're learning to use.

Two runners on parallel tracks, one tangled up in a long winding path full of loops, the other on a short straight path already crossing the finish line. — Same question, two routes. Only one of them leaves you time for the rest of the section.

And remember: on the Focus Edition you can review and change up to 3 answers per section. That's a nice safety net, but don't build your plan around it. If your first pass is clean, you won't need the net.

Here's your challenge for today. Pull up 10 Quant questions you've already done. For each one, solve it again WITHOUT setting up a single equation: test the answers or test values, and write every check on paper. Time yourself. Then look at how many of those 10 were faster the second way. I'll bet the number is bigger than you think. Then go train it until it's the first thing your hand does.