An employee at a restaurant prepares sandwiches and salads. It takes the employee 1.5 minutes to prepare a sandwich and...
GMAT Algebra : (Alg) Questions
An employee at a restaurant prepares sandwiches and salads. It takes the employee \(1.5\) minutes to prepare a sandwich and \(1.9\) minutes to prepare a salad. The employee spends a total of \(46.1\) minutes preparing \(\mathrm{x}\) sandwiches and \(\mathrm{y}\) salads. Which equation represents this situation?
\(1.9\mathrm{x} + 1.5\mathrm{y} = 46.1\)
\(1.5\mathrm{x} + 1.9\mathrm{y} = 46.1\)
\(\mathrm{x} + \mathrm{y} = 46.1\)
\(30.7\mathrm{x} + 24.3\mathrm{y} = 46.1\)
1. TRANSLATE the problem information
- Given information:
- 1.5 minutes to prepare each sandwich
- 1.9 minutes to prepare each salad
- x sandwiches prepared
- y salads prepared
- Total preparation time = 46.1 minutes
2. TRANSLATE each part into mathematical expressions
- Time spent on sandwiches: 1.5 minutes per sandwich × x sandwiches = \(\mathrm{1.5x}\) minutes
- Time spent on salads: 1.9 minutes per salad × y salads = \(\mathrm{1.9y}\) minutes
3. INFER the relationship for total time
- Total time = time for sandwiches + time for salads
- Therefore: \(\mathrm{1.5x + 1.9y = 46.1}\)
4. Match with answer choices
- The equation \(\mathrm{1.5x + 1.9y = 46.1}\) corresponds to Choice B
Answer: B
Why Students Usually Falter on This Problem
Most Common Error Path:
Weak TRANSLATE skill: Students mix up which coefficient goes with which variable, thinking "1.5 minutes for a sandwich" means the coefficient 1.5 should go with y (salads) instead of x (sandwiches).
This backwards thinking leads to the equation \(\mathrm{1.9x + 1.5y = 46.1}\), causing them to select Choice A (\(\mathrm{1.9x + 1.5y = 46.1}\)).
Second Most Common Error:
Poor TRANSLATE reasoning: Students recognize they need an equation but oversimplify by ignoring the different preparation times, thinking the total is just the sum of the quantities.
This leads them to write \(\mathrm{x + y = 46.1}\) and select Choice C (\(\mathrm{x + y = 46.1}\)).
The Bottom Line:
Success requires carefully tracking which time corresponds to which food item and translating "rate × quantity" relationships accurately into algebraic expressions.
\(1.9\mathrm{x} + 1.5\mathrm{y} = 46.1\)
\(1.5\mathrm{x} + 1.9\mathrm{y} = 46.1\)
\(\mathrm{x} + \mathrm{y} = 46.1\)
\(30.7\mathrm{x} + 24.3\mathrm{y} = 46.1\)