The cost to rent a commercial fishing boat from a certain company is $950 for the first 2 hours and...
GMAT Algebra : (Alg) Questions
The cost to rent a commercial fishing boat from a certain company is \(\$950\) for the first \(2\) hours and an additional \(\$50\) per hour for each hour after the first \(2\) hours. If the total cost to rent the commercial fishing boat from the company for \(\mathrm{t}\) hours, where \(\mathrm{t} \gt 2\), is \(\$1{,}100\), which equation represents this situation?
\(950(\mathrm{t} - 2) + 50\mathrm{t} = 1{,}100\)
\(950(2\mathrm{t}) + 50\mathrm{t} = 1{,}100\)
\(950 + 50(\mathrm{t} - 2) = 1{,}100\)
\(950 + 50(2\mathrm{t}) = 1{,}100\)
1. TRANSLATE the pricing structure
- Given information:
- \(\$950\) for the first 2 hours (fixed cost)
- \(\$50\) per hour for each hour after the first 2 hours
- Total cost for t hours is \(\$1,100\) (where \(\mathrm{t \gt 2}\))
2. INFER how to break down the cost components
- Since \(\mathrm{t \gt 2}\), we have two cost components:
- Fixed cost: \(\$950\) (covers first 2 hours regardless of how many total hours)
- Variable cost: depends on additional hours beyond the first 2
- Additional hours beyond first 2 = \(\mathrm{(t - 2)}\)
3. TRANSLATE the variable cost
- Cost for additional hours = \(\$50\) × (number of additional hours)
- Cost for additional hours = \(\$50 \times \mathrm{(t - 2)}\) = \(\mathrm{50(t - 2)}\)
4. INFER the total cost equation
- Total cost = Fixed cost + Variable cost
- Total cost = \(\mathrm{950 + 50(t - 2)}\)
5. Set up the equation
- Since total cost equals \(\$1,100\):
\(\mathrm{950 + 50(t - 2) = 1,100}\)
Answer: C
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students misinterpret the \(\$950\) as applying to each individual hour rather than as a flat rate for the first 2 hours combined.
They might think: "\(\$950\) per hour for first 2 hours, then \(\$50\) per hour after that." This leads them to create equations like \(\mathrm{950(t - 2) + 50t}\), incorrectly applying the \(\$950\) rate to the additional hours.
This may lead them to select Choice A (\(\mathrm{950(t - 2) + 50t = 1,100}\)).
Second Most Common Error:
Poor TRANSLATE reasoning: Students apply the additional \(\$50\)/hour rate to all t hours instead of just the additional hours beyond the first 2.
They correctly identify the \(\$950\) as a fixed cost but then think the \(\$50\) applies to every hour, creating: \(\mathrm{950 + 50(2t)}\) or similar variations.
This may lead them to select Choice D (\(\mathrm{950 + 50(2t) = 1,100}\)).
The Bottom Line:
The key challenge is carefully parsing the piecewise pricing structure—recognizing that different rates apply to different time periods, not different rates per hour throughout the entire rental period.
\(950(\mathrm{t} - 2) + 50\mathrm{t} = 1{,}100\)
\(950(2\mathrm{t}) + 50\mathrm{t} = 1{,}100\)
\(950 + 50(\mathrm{t} - 2) = 1{,}100\)
\(950 + 50(2\mathrm{t}) = 1{,}100\)