Question

Difficulty: MediumRatios, Rates, and Proportions

A landscape architect is designing a public park with a total area of 14,400 square feet14,400\text{ square feet}. The plan allocates space for a lawn, flowerbeds, and paved walkways in the ratio 7:3:27 : 3 : 2, respectively. How many more square feet of area are dedicated to the lawn than to the flowerbeds?

  1. A
    3,600
  2. 4,800Answer
  3. C
    5,760
  4. D
    6,000
  5. E
    8,400

Answer

4,800 square feet
The sum of all ratio parts is 7+3+2=127 + 3 + 2 = 12. Dividing the total park area of 14,400 sq ft14,400\text{ sq ft} by 1212 gives 1,200 sq ft1,200\text{ sq ft} per ratio part. The lawn accounts for 77 parts (8,400 sq ft8,400\text{ sq ft}) and the flowerbeds account for 33 parts (3,600 sq ft3,600\text{ sq ft}). Subtracting the flowerbed area from the lawn area gives 8,4003,600=4,800 sq ft8,400 - 3,600 = 4,800\text{ sq ft}. Alternatively, taking the direct difference of 73=47 - 3 = 4 parts and multiplying by 1,200 sq ft1,200\text{ sq ft} gives 4,800 sq ft4,800\text{ sq ft}.

Step-by-Step Solution

1
Find the total number of equal ratio parts.
7+3+2=12 parts7 + 3 + 2 = 12\text{ parts}
The complete park area is divided into portions defined by the sum of all terms in the ratio.
2
Calculate the area corresponding to one ratio part.
14,40012=1,200 square feet per part\frac{14,400}{12} = 1,200\text{ square feet per part}
Dividing the total area by the total number of parts determines the size of a single unit part.
3
Determine the difference in ratio parts between the lawn and the flowerbeds.
73=4 parts7 - 3 = 4\text{ parts}
The lawn receives 7 parts and the flowerbeds receive 3 parts.
4
Multiply the difference in parts by the area per part.
4×1,200=4,800 square feet4 \times 1,200 = 4,800\text{ square feet}
Multiplying the difference in ratio units by the unit area yields the total excess area of the lawn over the flowerbeds.

Key Concept

Solving multi-part ratio word problems using unit rate allocation per ratio part.
Estimated Time:1m 15s
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