For which of the following tables are all the values of x and their corresponding values of y solutions to...
GMAT Algebra : (Alg) Questions
For which of the following tables are all the values of x and their corresponding values of y solutions to the given inequality?
\(\mathrm{2x - y \gt 883}\)
| x | y |
|---|---|
| 440 | 0 |
| 441 | -2 |
| 442 | -4 |
| x | y |
|---|---|
| 440 | 0 |
| 442 | -2 |
| 441 | -4 |
| x | y |
|---|---|
| 442 | 0 |
| 440 | -2 |
| 441 | -4 |
| x | y |
|---|---|
| 442 | 0 |
| 441 | -2 |
| 440 | -4 |
1. TRANSLATE the problem requirements
- Given: Inequality \(\mathrm{2x - y \gt 883}\) and four tables with \(\mathrm{(x,y)}\) pairs
- Need to find: Which table has ALL pairs satisfying the inequality
2. INFER the systematic approach
- Since all tables use the same three x-values (440, 441, 442), I can find what y-constraint each x-value creates
- Then check which table's y-values satisfy ALL three constraints
3. SIMPLIFY to find y-constraints for each x-value
For x = 440:
- \(\mathrm{2(440) - y \gt 883}\)
- \(\mathrm{880 - y \gt 883}\)
- \(\mathrm{-y \gt 3}\)
- \(\mathrm{y \lt -3}\) (flip sign when dividing by -1)
For x = 441:
- \(\mathrm{2(441) - y \gt 883}\)
- \(\mathrm{882 - y \gt 883}\)
- \(\mathrm{-y \gt 1}\)
- \(\mathrm{y \lt -1}\)
For x = 442:
- \(\mathrm{2(442) - y \gt 883}\)
- \(\mathrm{884 - y \gt 883}\)
- \(\mathrm{-y \gt -1}\)
- \(\mathrm{y \lt 1}\)
4. APPLY CONSTRAINTS to evaluate each table
Choice A: \(\mathrm{x=440, y=0}\); \(\mathrm{x=441, y=-2}\); \(\mathrm{x=442, y=-4}\)
- For \(\mathrm{x=440}\): Is \(\mathrm{0 \lt -3}\)? No ✗ (fails immediately)
Choice B: \(\mathrm{x=440, y=0}\); \(\mathrm{x=442, y=-2}\); \(\mathrm{x=441, y=-4}\)
- For \(\mathrm{x=440}\): Is \(\mathrm{0 \lt -3}\)? No ✗ (fails immediately)
Choice C: \(\mathrm{x=442, y=0}\); \(\mathrm{x=440, y=-2}\); \(\mathrm{x=441, y=-4}\)
- For \(\mathrm{x=440}\): Is \(\mathrm{-2 \lt -3}\)? No ✗ (fails)
Choice D: \(\mathrm{x=442, y=0}\); \(\mathrm{x=441, y=-2}\); \(\mathrm{x=440, y=-4}\)
- For \(\mathrm{x=442}\): Is \(\mathrm{0 \lt 1}\)? Yes ✓
- For \(\mathrm{x=441}\): Is \(\mathrm{-2 \lt -1}\)? Yes ✓
- For \(\mathrm{x=440}\): Is \(\mathrm{-4 \lt -3}\)? Yes ✓ (all pass!)
Answer: D
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak SIMPLIFY skill: Forgetting to flip the inequality sign when dividing by -1
When solving \(\mathrm{-y \gt 3}\), students write \(\mathrm{y \gt -3}\) instead of \(\mathrm{y \lt -3}\). This creates the wrong constraint (\(\mathrm{y \gt -3}\) instead of \(\mathrm{y \lt -3}\)), making them think that larger y-values satisfy the constraint when actually smaller ones do. With incorrect constraints, they might select Choice A or B since these have \(\mathrm{y = 0}\) for \(\mathrm{x = 440}\), which would satisfy \(\mathrm{y \gt -3}\) but not the correct constraint \(\mathrm{y \lt -3}\).
Second Most Common Error:
Poor INFER reasoning: Not checking all three pairs systematically
Students might check just one or two pairs instead of verifying that ALL pairs satisfy the inequality. They might see that Choice A has \(\mathrm{(441,-2)}\) and \(\mathrm{(442,-4)}\) working and select it without noticing that \(\mathrm{(440,0)}\) fails the constraint. This leads to selecting Choice A prematurely.
The Bottom Line:
This problem tests whether students can correctly manipulate inequalities with negative coefficients and then systematically apply multiple constraints - both skills that require careful attention to detail.
| x | y |
|---|---|
| 440 | 0 |
| 441 | -2 |
| 442 | -4 |
| x | y |
|---|---|
| 440 | 0 |
| 442 | -2 |
| 441 | -4 |
| x | y |
|---|---|
| 442 | 0 |
| 440 | -2 |
| 441 | -4 |
| x | y |
|---|---|
| 442 | 0 |
| 441 | -2 |
| 440 | -4 |