\(3(\mathrm{kx} + 13) = \frac{48}{17}\mathrm{x} + 36\)In the given equation, k is a constant. The equation has no solution. What...
GMAT Algebra : (Alg) Questions
\(3(\mathrm{kx} + 13) = \frac{48}{17}\mathrm{x} + 36\)
In the given equation, \(\mathrm{k}\) is a constant. The equation has no solution. What is the value of \(\mathrm{k}\)?
1. TRANSLATE the problem information
- Given: \(3(\mathrm{kx} + 13) = \frac{48}{17}\mathrm{x} + 36\)
- Key condition: The equation has no solution
- Find: The value of k
2. INFER what "no solution" means
- A linear equation \(\mathrm{ax} + \mathrm{b} = \mathrm{cx} + \mathrm{d}\) has no solution when:
- The coefficients of x are equal (\(\mathrm{a} = \mathrm{c}\))
- BUT the constant terms are different (\(\mathrm{b} \neq \mathrm{d}\))
- This creates a contradiction like "5 = 7" which is impossible
3. SIMPLIFY the equation to standard form
- Expand the left side: \(3(\mathrm{kx} + 13) = 3\mathrm{kx} + 39\)
- Rewrite: \(3\mathrm{kx} + 39 = \frac{48}{17}\mathrm{x} + 36\)
- Now we can compare coefficients and constants
4. INFER the condition for no solution
- For no solution, coefficients must be equal:
\(3\mathrm{k} = \frac{48}{17}\) - Solve for k: \(\mathrm{k} = \frac{48}{17} \div 3 = \frac{48}{51} = \frac{16}{17}\)
5. SIMPLIFY the fraction
- \(\frac{48}{51} = \frac{16}{17}\) (dividing both numerator and denominator by 3)
Answer: \(\frac{16}{17}\) (or \(0.941, .9411, .9412\) in decimal form)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak INFER skill: Misunderstanding what "no solution" means algebraically
Students often think "no solution" means the equation equals zero or that they should solve for x. They might set up \(3(\mathrm{kx} + 13) = \frac{48}{17}\mathrm{x} + 36 = 0\), leading to incorrect algebraic manipulation. This confusion about the fundamental concept of "no solution" causes them to abandon systematic solution and guess among the answer choices.
Second Most Common Error:
Poor SIMPLIFY execution: Making arithmetic errors when handling fractions
Students correctly identify that coefficients must be equal (\(3\mathrm{k} = \frac{48}{17}\)) but make errors in the division: \(\mathrm{k} = \frac{48}{17} \div 3\). Common mistakes include forgetting to multiply by the reciprocal or incorrectly simplifying \(\frac{48}{51}\). This leads them to arrive at incorrect values that don't match any of the given answer forms.
The Bottom Line:
This problem tests whether students truly understand the algebraic meaning of "no solution" rather than just mechanical equation-solving. The key insight is recognizing that "no solution" creates specific structural requirements for the equation's coefficients and constants.