The function p satisfies \(\mathrm{p(2) = 11}\). The graph of \(\mathrm{y = q(x)}\) is obtained by shifting the graph of...
GMAT Advanced Math : (Adv_Math) Questions
The function \(\mathrm{p}\) satisfies \(\mathrm{p(2) = 11}\). The graph of \(\mathrm{y = q(x)}\) is obtained by shifting the graph of \(\mathrm{y = p(x)}\) upward 3 units and then downward 9 units. What is the value of \(\mathrm{q(2)}\)?
2
5
14
17
1. TRANSLATE the transformation information
- Given information:
- \(\mathrm{p(2) = 11}\)
- Graph of \(\mathrm{q(x)}\) comes from shifting \(\mathrm{p(x)}\) upward 3 units, then downward 9 units
- Need to find: \(\mathrm{q(2)}\)
- What the shifts mean mathematically:
- "Upward 3 units" → add 3 to every y-value
- "Downward 9 units" → subtract 9 from every y-value
2. INFER how to combine the shifts
- These transformations happen in sequence, so we can combine them
- Net vertical shift = \(+3 - 9 = -6\) units
- This means every point on \(\mathrm{p(x)}\) moves down 6 units to create \(\mathrm{q(x)}\)
- Therefore: \(\mathrm{q(x) = p(x) - 6}\)
3. SIMPLIFY to find the specific value
- Since \(\mathrm{q(x) = p(x) - 6}\), we have:
\(\mathrm{q(2) = p(2) - 6}\)
\(\mathrm{q(2) = 11 - 6}\)
\(\mathrm{q(2) = 5}\)
Answer: B (5)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students correctly understand that upward means +3 and downward means -9, but incorrectly think both shifts work in the same direction, treating the net shift as \(+3 + 9 = +12\) or calculating the net as +6 instead of -6.
If they use +6: \(\mathrm{q(2) = 11 + 6 = 17}\)
This may lead them to select Choice D (17)
Second Most Common Error:
Incomplete INFER reasoning: Students apply only one of the two shifts instead of combining them.
- Applying only the upward shift: \(\mathrm{q(2) = 11 + 3 = 14}\) → Choice C (14)
- Applying only the downward shift: \(\mathrm{q(2) = 11 - 9 = 2}\) → Choice A (2)
The Bottom Line:
This problem tests whether students can systematically handle sequential transformations. The key insight is recognizing that "upward then downward" creates a net effect that can be calculated as a single transformation.
2
5
14
17