The function h is defined by the equation \(\mathrm{h(t) = 500 - 2(t - 10)^2}\). What is the value of...
GMAT Advanced Math : (Adv_Math) Questions
The function h is defined by the equation \(\mathrm{h(t) = 500 - 2(t - 10)^2}\). What is the value of \(\mathrm{h(3)}\)?
394
514
402
598
1. TRANSLATE the problem information
- Given information:
- Function: \(\mathrm{h(t) = 500 - 2(t - 10)^2}\)
- Need to find: \(\mathrm{h(3)}\)
- This means substitute \(\mathrm{t = 3}\) into the function expression
2. SIMPLIFY through systematic substitution
- Start with the function: \(\mathrm{h(t) = 500 - 2(t - 10)^2}\)
- Substitute \(\mathrm{t = 3}\): \(\mathrm{h(3) = 500 - 2(3 - 10)^2}\)
3. SIMPLIFY using order of operations
- Work inside parentheses first: \(\mathrm{(3 - 10) = -7}\)
- So we have: \(\mathrm{h(3) = 500 - 2(-7)^2}\)
4. SIMPLIFY the exponent
- Calculate \(\mathrm{(-7)^2}\): \(\mathrm{(-7)^2 = 49}\) (remember: negative squared equals positive)
- Now we have: \(\mathrm{h(3) = 500 - 2(49)}\)
5. SIMPLIFY the final calculation
- Multiply: \(\mathrm{2 \times 49 = 98}\)
- Subtract: \(\mathrm{500 - 98 = 402}\)
Answer: C. 402
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak SIMPLIFY skill: Sign error when squaring the negative number
Students often think that \(\mathrm{(-7)^2 = -49}\), forgetting that when you square any number (positive or negative), the result is always positive. With this error:
- \(\mathrm{h(3) = 500 - 2(-49) = 500 - (-98) = 500 + 98 = 598}\)
This may lead them to select Choice D (598).
Second Most Common Error:
Poor SIMPLIFY execution: Order of operations confusion
Some students might calculate \(\mathrm{2(3 - 10)^2}\) as \(\mathrm{2(3) - 10^2}\), getting \(\mathrm{6 - 100 = -94}\), then \(\mathrm{500 - (-94) = 594}\). Or they might make other arithmetic errors in the multi-step calculation process.
This leads to confusion and guessing among the remaining answer choices.
The Bottom Line:
This problem tests careful execution of order of operations and proper handling of negative numbers in exponents. The key insight is remembering that squaring always produces a positive result, regardless of whether the base is positive or negative.
394
514
402
598