Line k is defined by y = 17/7x + 4. Line j is parallel to line k in the xy-plane....
GMAT Algebra : (Alg) Questions
Line \(\mathrm{k}\) is defined by \(\mathrm{y = \frac{17}{7}x + 4}\). Line \(\mathrm{j}\) is parallel to line \(\mathrm{k}\) in the xy-plane. What is the slope of line \(\mathrm{j}\)?
\(\frac{7}{17}\)
\(\frac{17}{7}\)
\(4\)
\(17\)
1. TRANSLATE the problem information
- Given information:
- Line k: \(\mathrm{y = \frac{17}{7}x + 4}\)
- Line j is parallel to line k
- Need to find: slope of line j
2. TRANSLATE the equation format
- The equation \(\mathrm{y = \frac{17}{7}x + 4}\) is in slope-intercept form: \(\mathrm{y = mx + b}\)
- In this form: \(\mathrm{m = slope}\), \(\mathrm{b = y-intercept}\)
- Therefore: slope of line k = \(\mathrm{\frac{17}{7}}\), y-intercept = \(\mathrm{4}\)
3. INFER the relationship between parallel lines
- Parallel lines have identical slopes
- Since line j is parallel to line k, they must have the same slope
- Slope of line j = slope of line k = \(\mathrm{\frac{17}{7}}\)
Answer: B. \(\mathrm{\frac{17}{7}}\)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students confuse the slope with the y-intercept in the equation \(\mathrm{y = \frac{17}{7}x + 4}\).
They see the number 4 at the end and think this represents the slope, forgetting that in \(\mathrm{y = mx + b}\) form, the coefficient of x is the slope. This may lead them to select Choice C (\(\mathrm{4}\)).
Second Most Common Error:
Poor TRANSLATE reasoning: Students incorrectly flip the fraction \(\mathrm{\frac{17}{7}}\) to get \(\mathrm{\frac{7}{17}}\).
This typically happens when students misremember slope formulas or get confused about which number should be in the numerator versus denominator. This may lead them to select Choice A (\(\mathrm{\frac{7}{17}}\)).
The Bottom Line:
This problem tests whether students can correctly identify slope from standard form equations and remember that parallel lines share the same slope - two fundamental concepts that require careful attention to mathematical notation.
\(\frac{7}{17}\)
\(\frac{17}{7}\)
\(4\)
\(17\)