Great inequality question that tests whether you can connect algebraic manipulation with constraint application. Let me walk you through the core approach that'll help you crack this one.
Here's how to think about this:Step 1: Solve for x in terms of bYou've got the equation \(2x - 3b = 0\). Let's isolate x to see how it relates to b.
\(2x - 3b = 0\)
\(2x = 3b\)
\(x = \frac{3b}{2}\)
So x is always three-halves times whatever b is. This relationship is your key to the whole problem.
Step 2: Apply the constraint on bNow here's the critical insight: you know that \(b < 2\), and you've just found that \(x = \frac{3b}{2}\).
Since \(b < 2\), let's multiply both sides by \(\frac{3}{2}\):
\(\frac{3b}{2} < \frac{3(2)}{2}\)
\(\frac{3b}{2} < 3\)
Notice that \(\frac{3}{2}\) is positive, so the inequality direction stays the same (this is crucial - you don't flip the sign when multiplying by a positive number).
But remember, \(x = \frac{3b}{2}\), which means:
\(x < 3\)
Step 3: Match with answer choicesLooking at the options:
- \(x > -3\): Could be true, but not necessarily for all values
- \(x < 2\): Too restrictive - x could be 2.5, for example
- \(x = 3\): Only true if b = 2, but we know \(b < 2\)
- \(x < 3\): This is exactly what we derived!
- \(x > 3\): Contradicts our finding
Answer: (D) \(x < 3\)The key here was recognizing that the constraint on b translates directly to a constraint on x through their relationship. Since b must be less than 2, and x equals \(\frac{3b}{2}\), then x must be less than 3.
Want to master this question type systematically?The complete solution on Neuron shows you the
systematic framework for inequality constraint problems, including an alternative "smart numbers" approach and the common traps students fall into (like choosing option A instead of D). You'll also see how to spot when to flip inequality signs and when not to - a pattern that shows up across many GMAT questions. Check out
Neuron's complete library of official questions with detailed solutions to build rock-solid fundamentals for test day.