GED Mathematical Reasoning TestQuantitative Problem Solving with Rational NumbersMedium
A rectangular swimming pool is 25 meters long and 10 meters wide. A safety rope needs to be placed around the perimeter of the pool. If the rope costs $1.50 per meter, what is the total cost of the rope?
- A$75.00
- B$105.00
- C$150.00
- D$52.50
Show answer & explanationAnswer & explanation
Correct answer: B. $105.00
First, calculate the perimeter of the rectangular pool: P = 2 * (length + width) = 2 * (25m + 10m) = 2 * 35m = 70m. Then, multiply the perimeter by the cost per meter: 70m * $1.50/m = $105.00.
Why the other options are wrong
- A. This might be if the perimeter was 50m, not 70m.
- C. This is an overestimation, possibly an error in perimeter or cost calculation.
- D. This is an incorrect perimeter calculation or an arithmetic error.
Perimeter and Cost Calculation
To calculate the total cost of a material needed for a perimeter, first find the perimeter of the shape, then multiply that length by the cost per unit of length.
- Perimeter of a rectangle: P = 2(l + w).
- Total cost = Perimeter * Cost per unit.
- Units must be consistent (e.g., meters and dollars per meter).
Memory trick: Outline, then multiply by price.