Question

a contractor uses the data in this table to calculate the cost of building a fence around rectangular site a. here is the contractor’s work: 50 ft × 20 ft × $5 per sq ft = $5,000 a project manager reviews the contractor’s work. at which step will the project manager find an error?
site | length | width | fencing cost | paving cost
site a | 50 ft | 20 ft | $5 per ft | $9 per sq ft
site b | 60 ft | 40 ft | $6 per ft | $8 per sq ft
a) checking the work against the data for recording errors.
b) checking that the correct formula was used for this situation and the order of operations was followed.
c) checking the work for calculation errors.
d) the contractor’s work is correct.

Explanation:

Step1: Identify fencing calculation need

Fencing requires perimeter, not area.
Perimeter of rectangle: $P = 2\times(length + width)$

Step2: Calculate correct perimeter for Site A

$P = 2\times(50 + 20) = 2\times70 = 140$ ft

Step3: Analyze contractor's error

Contractor calculated area ($50\times20$) and used sq ft cost, but fencing uses per ft cost on perimeter. The error is wrong formula/operation.

Answer:

B) Checking that the correct formula was used for this situation and the order of operations was followed.