\(\mathrm{g(x) = 3(8 - x)}\) For the function g defined above, what is the value of \(\mathrm{g(2)}\)?...
GMAT Advanced Math : (Adv_Math) Questions
\(\mathrm{g(x) = 3(8 - x)}\)
For the function g defined above, what is the value of \(\mathrm{g(2)}\)?
6
22
30
18
1. TRANSLATE the problem requirement
- Given: \(\mathrm{g(x) = 3(8 - x)}\)
- Find: \(\mathrm{g(2)}\)
- What this means: Substitute \(\mathrm{x = 2}\) into the function
2. SIMPLIFY through substitution and calculation
- Substitute \(\mathrm{x = 2}\): \(\mathrm{g(2) = 3(8 - 2)}\)
- Work inside parentheses first: \(\mathrm{g(2) = 3(6)}\)
- Multiply: \(\mathrm{g(2) = 18}\)
Answer: D (18)
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak SIMPLIFY execution - Order of operations confusion: Students might incorrectly calculate \(\mathrm{3 \times 8 - 2 = 24 - 2 = 22}\), forgetting that the subtraction should happen inside the parentheses first.
This may lead them to select Choice B (22).
Second Most Common Error:
Incomplete SIMPLIFY process: Students correctly find \(\mathrm{8 - 2 = 6}\) but forget to multiply by 3, stopping at just the result inside the parentheses.
This may lead them to select Choice A (6).
The Bottom Line:
This problem tests whether students understand function notation and can systematically follow order of operations. The key is remembering that parentheses must be evaluated before multiplication, and that finding \(\mathrm{g(2)}\) requires complete substitution and simplification.
6
22
30
18